Talk:Color blindness/Archive 1

Misconceptions, request for references

I have tried to get rid of most of the errors in this page (and put in a warning against recreating them, though I don't suppose it will work: people have got it so firmly into their heads that there is a red cone and that people have primary colours). Can anyone now document:

• the claim that in emergency situations everyone is colour blind? (from first principles, I don't actually believe this, but I suppose it might be true)
• the high frequency of colour blindness in small-gene-pool (basically, inbred) communities? (I am fairly sure this is right, from individuals I've talked to, but we really need a proper reference).

For monochromats, this is the subject of Oliver Sacks's book Island of the colorblind. Not the most scientific source, but good enough. I dunno about dichromats, but it's pretty believeable.

seglea 21:58, 14 Apr 2004 (UTC)

In addition, "Some color-blind people have better night vision than those with normal color vision.", seems to be pretty strongly refuted by http://vision.psychol.cam.ac.uk/jdmollon/papers/hudibras.pdf. You could say that monochromats are better off in the first few minutes after sudden dark onset, but is this worth saying?

On the other hand, "Color blind hunters are better at picking out prey against a confusing background, and the military have found that color blind soldiers can sometimes see through camouflage that fools everyone else." Appears to be valid, if anyone was wondering (I was) http://www.hubmed.org/display.cgi?uids=1354367.

I, too, would be interested in seeing a reference for the claim that everyone is blind in emergency situations. If it can't be backed up, it should be removed. Edwardian 06:52, 31 July 2005 (UTC)

the link to "color blind people can see through camouflage" is misrepresented and given undue prominence for an obscure reference which had only 7 people in the study. also that article refers to textures which is quite different from color vision. this statement should be removed unless you can find a reference that contradicts this: http://www.airborneranger.com/forums/lofiversion/index.php/t17.html and other sites which say that normal color vision is mandatory for SOTIC (sniper).

Removed images

Since neither of the images on the pages were working for their intended purpose, I've removed them. I could definitely see "WIKI" in the first and "WIKIPEDIA" in the second. - UtherSRG 13:28, 5 May 2004 (UTC)

On my talk, Hankwang replies:

In case you're not watching Talk:color blindness: we have been discussing how to construct our own color blindness tests over the past week, and if you are color blind, we would welcome your input on the talk page. Do you see difference between the various spectra shown at the bottom of the talk page? Do you know whether you're are protanopic or deuteranopic? (Both are forms of red-green color blindness, as you probably already know).

I haven't been following along. It smacks of primary research to me. It would be far more appropriate to give two sample Ishihara plates (one for control, and one that dichromats and all three anomalous trichromats will fail on). This could probably be considered fair use. I do not know if I'm deuteran- or protanamalous, but I do know I'm a trichromat and not a dichromat. - UtherSRG 13:54, 5 May 2004 (UTC)

Our "primary research" is an effort to make sense out of the published data that is not documented very clearly on the web. Unfortunately, we lack books on the topic.

It is fundamentally impossible to detect a protanomalous or deuteranomalous person with an Ishara-like plate that is reproduced with normal CMY print or on an RGB display.

Han-Kwang (talk) 14:08, 5 May 2004 (UTC)

I don't believe you are correct... the plates work for me (ie I can see some but not others) on online images, although they don't work as well as the true plates. However, that's not my point. My point is that we should provide a sample of what exists (secondary research) not create our own version purely from descriptions and technical manuals (primary research). Shorter: The article should not include a valid working test, it should show what a test looks like. - UtherSRG 14:24, 5 May 2004 (UTC)

It might be interesting to take a look at Wikiresearch, which is an effort to set up a wiki for original research. 82.117.135.78 13:40, 19 May 2004 (UTC)

Color blindness test

[discussion started on user talk pages]

redgreen.png

Are sure that this picture is a good color blindness test? In each of the green channel, the red channel, and the luminosity channel, the letters are recognizable. Update: my protano(p|mal)ic colleague said that he couldn't really tell whether the picture is green or red, but he clearly sees a two bright letters (the green ones) and two dark letters (the red ones).

Such a picture should look like more or less monochromatic intensity noise to a color-blind person, while information about the letters "WIKI" is in the color balance. Remember that for someone with normal color vision, green stimulates all three receptors and red stimulates the green and red receptors. Someone who misses the red receptors can still distinguish green from red because of the difference in blue stimulus. Hence, you need to mix in a bit of blue into the red to make the two indistinguishable. More precisely, R, G, and B on a CRT stimulate the receptors in (roughly) the ratios (0.7,0.3,0), (0.3,0.65,0.05), and (0.15:0.02:0.83) - see CIE diagram on the color page. The trick is to find RGB values that will have the same stimulus ratio for the green/blue receptors, so that they look as intensity differences. And then you have to keep in mind that the intensities on your screen are proportional to the RGB values to the power 2.5 (see gamma correction). It's not trivial...

Han-Kwang (talk) 14:41, 26 Apr 2004 (UTC)

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Wik ipe dia

Based on the information you gave, if I understood and got everything right (I could easily have made a mistake or 15), then the WIK, IPE and DIA in the new image should be detectable respectively by the red, green and blue receptors only. It's many years since I saw an actual colour test, so I don't know if it looks like normal tests or not. (I think they normally have dots instead of crystals.) Does your colleague read "WIKIPEDIA" or "IPEDIA" now? Κσυπ Cyp   18:53, 26 Apr 2004 (UTC)

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If I had known that you would immediately make a new version of the picture, then I would have checked my facts better. :-) Anyway, my test person was not available today, but one can always construct theories. You have now made the letters such that they are visible in only one of the three (R/G/B) channels; that was not what I meant.

According to this Color FAQ, a typical CRT has the following stimuli, which are a bit different from the ones that I roughly estimated:

              R        G        B      |  white (6500 K)
x (L cones)   0.640    0.300    0.150  |  0.3127     
y (M cones)   0.330    0.600    0.060  |  0.3290     
z (S cones)   0.030    0.100    0.790  |  0.3582

I forgot to mention that the values of R/G/B are scaled such that RGB=(1,1,1) gives a 6500 K (D65) white on a properly-calibrated CRT display. Judging from your user page, you shouldn't be too scared of a bit of math. :-) So, the above table says that (x,y,z) = A.(R,G,B), where A is the 3x3 matrix above. Find scaling factors (a1,a2,a3) such that A.(a1,a2,a3) = (xw,yw,zw) (the white point). Then you can construct a new matrix B, with $B_{ij}=A_{ij}a_{i}$. Update: this should be Bij = Aij aj (not ai)! Then the tristimulus values can be directly evaluated from the computer screen RGB values as (x,y,z)=B.(R,G,B), except that the numbers in your paint program are proportional to the power (1/2.5) of the true RGB intensities.

Now you have to find metameric black for someone missing x (long-wavelength) receptors, that is an RGB vector (r',g',b') that you can add to any RGB vector without changing the perception for that person. Construct a 3x2-matrix C which is the rows of B corresponding to y and z. Solve

C.(r',g',b') = (0,0)

Any vector in the solution space can be added to any (RGB) vector without a protanopic seeing the difference, of course with the restriction that (R+r',G+g',B+b') stays within the allowed range of positive values. You appear to have taken (p,0,0) (any value of p) as a solution, but it would look more like p(+1,-0.5,+0.1) (roughly, I'm too lazy to do the matrix inversions now)

Now you can construct an image with random, not too-saturated, colors, and add an appropriate amount of (r',g',b') to all color spots that you want to highlight for a person with normal color vision. Don't forget the gamma exponent to convert between computer RGB values and actual intensities.

Actually, it is probably easier to steal the palette from any other color-blindness test, e.g. here, that is on the web than to calculate the color palette. :-)

On a TFT display, the coefficients are probably different. People with protanomaly instead of protanopia need different colors as well.

Han-Kwang (talk) 12:35, 27 Apr 2004 (UTC)

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Whatever, I decided to install Octave (Mathlab clone), learn how to use it, and implement the stuff above, see colorblindpalette.m (description), with a suggestion for color palettes to use. However, it is untested. I suggest that you create your mosaic with random colors 1-10, add 10 to the palette index values for the first "red" word, 20 to the palette index values for the second "green" word, and 30 for the third "blue" word.

Han-Kwang (talk) 14:08, 27 Apr 2004 (UTC)

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I've updated the matrix in the program I wrote to convert from LMS to RGB colour, and after finding out that .bmp files are not only stored upsidedown, but also use BGR colour (!!!) instead of RGB colour, fixed the program. Maybe it looked like I just had each line in each screen-primary colour because of the RGB/BGR confusion, so the colours weren't "mixed" correctly. In any case, it now correctly uses the (updated) inverse matrix. (My pocket calculator conveniently does matrix inversion.)

Here's the actual program, if you can read C, and feel like checking for bugs or using it for anything... A crash means it can't find the file - I was lazy. Κσυπ Cyp   16:41, 27 Apr 2004 (UTC)

#include <math.h>
#include <stdio.h>

unsigned char asdf[54], rgb[3];

/*double mat[3][3]={
{1.768472906,  -.7931034483, -.3004926108},
{-.8177339901, 1.908045977,   .1018062397},
{ .0492610837, -.1149425287, 1.198686371 }};
*/
double mat[3][3]={
{ 2.088353414,  -.9906291834, -.3212851406},
{-1.155287818,  2.236055332,   .0495314592},
{  .0669344043, -.245426149,  1.271753681 }};

int main() {
  FILE *i, *o;
  double R, G, B, L, S, M;
  /* input file has L "red", M "green", and S "blue" stimuli values */
  i=fopen("c:\\projects2\\colours.bmp", "rb");
  /* we will calculate the RGB values that generate the above stimuli */
  o=fopen("c:\\projects2\\colours.out.bmp", "wb");
  fread(asdf, 54, 1, i);
  fwrite(asdf, 54, 1, o);
  while(1==fread(rgb, 3, 1, i)) {
    /* rgb[] contains LSM values, scaled such that (255,255,255) = white point */
    /* Convert to unscaled LSM - I think M an S were previously swapped here. */
    L=rgb[2]*.3127/255; S=rgb[1]*.329/255; M=rgb[0]*.3582/255;
    /* calculate RGB from LMS (again, not LSM) */
    R=L*mat[0][0]+M*mat[0][1]+S*mat[0][2];
    G=L*mat[1][0]+M*mat[1][1]+S*mat[1][2];
    B=L*mat[2][0]+M*mat[2][1]+S*mat[2][2];
    /* Scaling so LMS(.3127,.329,.3582)==RGB(1,1,1) (LMS?)  */
    R/=.2120267738; G/=.3921458724; B/=.3957273539;
    /* Gamma correction and scaling to 0..255 */
    R=pow(R, .4);
    G=pow(G, .4);
    B=pow(B, .4);
    rgb[2]=R*255.; rgb[1]=G*255.; rgb[0]=B*255.;
    fwrite(rgb, 3, 1, o);
  };
  fclose(i); fclose(o);
}

---

The above picture is no better from the first one. In fact, I can read it much more easily then the first one! (I'm deuteranopic, I normally fail to see anything on most of the real test pictures).

I came to believe that part of the problem is that you are mixing the three tests together. But even if I don't see the first three letters very well, I see the continuation of the string and the string is obvious. Then my brain helps my eyes to see the WIK. So someone has to a) find a better pallete and b) make different tests with different strings for different purposes.

If you need help, please contact me on hanke at volny dot cz and we can cooperate to create a better picture.

I'm moving here my comment from above:

It seems to me that the image on this page doesn't illustrate the problem very well. I'm a deuteranopic (meaning I have troubles distinguishing red and green) and I fail most of the common-used tests that are available on the internet. Still, I can distinguish the red and the green letters on the image in this wiki-page quite well. I mean, color-blindness is defined more strictly than that. But you could try to ask at http://members.aol.com/protanope/card1.html if they would permit Wikipedia as an encyclopedia to use one of their images.

user:hhanke

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I wonder if the use of "polygons" rather than the usual dots is making the tests not work as well as they should. The eye is much better at noticing an edge between two slightly dissimilar shades, rather than comparing two shades separated by white space (the white background of the dots in a typical colour-blindeness test). So that may be causing the problem, even if the colours are very close to being corect. -- DrBob 18:10, 27 Apr 2004 (UTC)

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1

2

Another attempt, not sure how to do it properly without writing my own drawing program... What are the letters/numbers there, and are they easy or hard to read? The letter picture is aimed at protanopia, the number picture at deuteranopia. Κσυπ Cyp   19:38, 27 Apr 2004 (UTC)

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To Cyp: I made a mistake in my equations (see Update-text), but you seem to have used common sense instead of blindly copying equations. :) About your C program: I added comments to what I believe it does. Clever to start with a file that has LMS instead of RGB values, however you seem to use LSM (long=red, short=blue, medium=green), which I suppose you didn't mean to do since then you'd need a different matrix.

About the new "spots on white background" pictures: I see a greenish 8 and a hard-to-distinguish greyish 4 on a brownish background in one picture. The other one clearly shows a red P and a blue G on a green background. I played a bit with the color balance on my CRT, but to no avail. I assume that that's because of the LSM bug. I suppose that you could make the background a bit more noisy, both in intensity and in hue. -- Han-Kwang (talk) 21:29, 27 Apr 2004 (UTC)

---

This one is much better than the previous picture. I'm deuteranopic and I'm not sure what there really is on these pictures, but after a little time of looking at it it seems to me that there is a 4 over an eight in the left picture. One of the letter is G (but I didn't notice the P, if there really is one). It still needs some work, because on most of the tests I was given by my doctor (the ones relevant to my illness of course) I didn't see *anything*, not even after looking at it for longer time.

Another thing: a reference image that can be seen by all (even the ones with the eye defect like me) should be made in the same style (but with obvious colors) and put as the first image of the test, just as a reference. This is how it's usually done and it's important so that the test subject knows what is it that he should see. (If you don't have any reference, you could for example think that you have seen *something* and this is all, but after you have seen a reference image, you know the rules of the game and you know that unless you clearly see a number or letter, your vision is altered.) But it's important to put a different letter or number on the reference image as not to ruin the test itself. -- hhanke

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I called them rgb or RGB, then changed the letters to LSM (I guess I was thinking Long, Short and Micro or something...) just before copying the code here. The LSM/LMS mixup doesn't affect the code semantics.

The left picture looks to me like a (relatively) clear 8, with a very easy to miss 4 in the background, and the right picture looks like a very clear P (clearer than the 8) with a slightly-easier-to-see-than-intended G in the background. Since you can't see the P but can see the 8, I'm tempted to either declare that you are actually protanopic, not deuteranopic, or to redefine the terms, to make the results be as expected...

I suppose that out of the images I've drawn, the P/G image would be the best to have on the page, then... (Even though it doesn't test for the same thing it was intended to...)

I'm curious how the L, M and S receptors are stimulated as a function of light frequency... (Might make it possible to draw a more realistic spectrum at colour. Κσυπ Cyp   22:00, 30 Apr 2004 (UTC) ---

response curves

See cone cell for the spectral response curves which I added recently - they are quite surprising -- DrBob 22:38, 30 Apr 2004 (UTC)

I saw that graph before. Do you know what the function for the graph is, or what data was used to draw it? Κσυπ Cyp   13:00, 1 May 2004 (UTC)

---

Well, I'm not entirely sure I'm suffering of deuteranopia. I was only told by my doctor that I have a red-green deficiency which can be equaly deuteranopia that protanopia. But on this site: [[1]] I see the images "normal" and "deuteranopia" as identical and the "protanopia" is clearly different for me. So I think I'm deuteranopic if these images aren't switched. --hhanke

---

It must have been late when I wrote my previous comment. I'm not sure what I was thinking.Apparently I got so confused by the permutation of the variable names' that I thought that you used the wrong coefficients for the white-point normalization. :-) Also, my earlier remark about protanomalics/deuteranomalics is wrong; you can't test that with a 3-phosphor CRT.

Re the spectra of the receptors: the spectra for a "Standard Observer" are specified by CIE. The hard part is to find a plot on the web. This page provides the raw data (under "Standard observer"). It's weird that these calculated pictures do not work. It can be the color balance of the CRT on which it is viewed (it should be 6500 K). TFT screens have a different color rendering. Maybe it is the display gamma? There was something with Macintoshes having a gamma of 2.2 under certain conditions. Or the standard CRT RGB matrix deviates too much from reality?

The data in the link I provided give an L-curve that has two maxima, quite different from the spectrum in the cone cell page.

Han-Kwang (talk) 23:01, 30 Apr 2004 (UTC)

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Huh, I plotted the CIE data and it's indeed rather different. Reading the reference I got my graph from, it seems its data comes directly from spectrophotometry of the cone cells themselves, but says that there's a whole bunch of processing that goes on after that, in the retinal membrane and the brain. This colour vision stuff is more complex that it looks. -- DrBob 00:29, 1 May 2004 (UTC)

Cone fundamentals and generating a spectrum

[Continued from previous discussion]

It turns out that the functions in my link are not cone spectra but rather color matching functions (explanation). If I get it right, CMFs are a linear combination of the cone spectra, for some reason practical to use in calculations if you know what you're doing (does not apply to us, apparently :-). The cone spectra we are interested in are called cone fundamentals. Those look more like your DrBob's spectra.

Maybe it's time for an article that goes into the mathematics of color vision?

-- Han-Kwang (talk) 13:25, 3 May 2004 (UTC)

The cone spectra fundamental text page looks like what I was looking for, except each cone has a different scale.

Here's what I got, although the L, M and S cones are probably incorrectly scaled, and I've just used the same matrix assuming it was still correct. At least the regular spectrum looks a bit like a real spectrum, unlike most rainbows on the internet...

Do any pairs of spectrums appear identical? (Or at least, rather similar?) Κσυπ Cyp   12:03, 4 May 2004 (UTC)

← Regular

← Protanopic

← Deuteranopic

← Tritanopic

And the program: (There must already be a spectrum.bmp, in 24 bit colour, 441x80 pixels. Contents of spectrum.bmp otherwise irrelevant and will be erased.)

#include <math.h>
#include <stdio.h>

unsigned char asdf[54], rgb[3];

/*double mat[3][3]={
  {1.768472906,  -.7931034483, -.3004926108},
  {-.8177339901, 1.908045977,   .1018062397},
  { .0492610837, -.1149425287, 1.198686371 }};
*/
double mat[3][3]={
  { 2.088353414,  -.9906291834, -.3212851406},
  {-1.155287818,  2.236055332,   .0495314592},
  {  .0669344043, -.245426149,  1.271753681 }};

double table[441][3]; // wavelength-390, SML

double unused;

int zero=0;

int main() {
  FILE *i, *o;
  double R, G, B, L, M, S, f;
  int x, y;
  if(!(i=fopen("c:\\projects2\\spectrum.bmp", "rb")))
    {printf("File not found.\n");return(0);}
  fread(asdf, 54, 1, i);
  fclose(i);
  if(!(i=fopen("c:\\projects2\\ss2_10e_1.txt", "rt")))
    {printf("File2 not found.\n");return(0);}
  // read cone SML spectra (convert from log to linear)
  for(x=0;x<226;++x)
    fscanf(i, "%lf,  %lf,  %lf,  %lf",
	   &unused, &table[x][0], &table[x][1], &table[x][2]);
  for(   ;x<441;++x) {
    fscanf(i, "%lf,  %lf,  %lf,",
	   &unused, &table[x][0], &table[x][1]); table[x][2]=-1e99; }
  for (x=0;x<441;++x)
    for(y=0;y<3;++y)
      table[x][y]=exp(table[x][y]);
  for(x=0,L=M=S=0;x<441;++x) { L+=table[x][0]; M+=table[x][1]; S+=table[x][2]; } //Integrate
  L=1/L; M=1/M; S=1/S; f=(L+M+S)/3; L/=f; M/=f; S/=f; //Correct proportion, but keep overall intensity about the same (otherwise image would either appear black, or so bright the computer screen catches on fire (at least, if it didn't overflow first...))
  for(x=0;x<441;++x) { table[x][0]*=L; table[x][1]*=M; table[x][2]*=S; }
  fclose(i);
  // create new bitmap (loop over x,y coordinates)
  o=fopen("c:\\projects2\\spectrum.bmp", "wb");
  fwrite(asdf, 54, 1, o);
  for(y=79;~y;--y) { 
    if(y<20) f=0; // black
    else if(y<30)  // fuzzy transition black-bright
      f=1-cos((y-20)*(3.1415626935897932384626433832795/10));
    else f=2; // full brightness
    for(x=0;x<441;++x) {
      L=table[x][0]/20.; M=table[x][1]/20.; S=table[x][2]/20.; //Scale values to a sensible range
      L*=f; M*=f; S*=f;
      x+=390; // wavelength offset
      // ruler
      if(y>=55&&x%  5) L=M=S=0; 
      if(y>=60&&x% 10) L=M=S=0;
      if(y>=65&&x% 50) L=M=S=0;
      if(y>=70&&x%100) L=M=S=0;
      if(y>=75&&x%500) L=M=S=0;
      x-=390;
      //Add background colour to entire image
#define sp(c,i,s) (i*exp((double)(x-c)*(double)(c-x)/(double)(s*s)))
    L+=.009+sp(55,.0346,50); //Flat background isn't as good at keeping final values between 0 and 1...
    M+=.009+sp(55,.0346,50);
    S+=.009+sp(55,.0346,50);
//      L+=.5; M+=.5; S+=.5;
      // uncomment one of these lines to generate color-blind versions. The
      // missing stimulus is an (arbitrary) weighted sum of the other two.
      //L=      M*.9+S* .1; //Pro
      //M=L*.95     +S*.05; //Deu
      //S=L*.5 +M*.5      ; //Tri
      if(R<0||R>1) R=((x^y)&2)/2; if(G<0||G>1) G=((x^y)&2)/2; if(B<0||B>1) B=((x^y)&2)/2; //Sanity check - checkered pattern means values out of range.
      R=L*mat[0][0]+M*mat[0][1]+S*mat[0][2];
      G=L*mat[1][0]+M*mat[1][1]+S*mat[1][2];
      B=L*mat[2][0]+M*mat[2][1]+S*mat[2][2];
      //Scaling so  LMS(.3127,.329,.3582)==RGB(1,1,1)
      R/=.2120267738; G/=.3921458724; B/=.3957273539;
      // gamma correction and write to BMP
      R=pow(R, .4);  G=pow(G, .4); B=pow(B, .4);
      rgb[2]=R*255.; rgb[1]=G*255.; rgb[0]=B*255.;
      fwrite(rgb, 3, 1, o);
    } 
    fwrite(&zero, 1, 1, o); /*Dumb rounding line length up to 4 bytes...*/ }
  fclose(o);
  //for(x=0;x<441;++x) printf("%d, %ld, %ld, %lf
}

---

The cone spectra in the mentioned webpage are normalized to amplitude 1. The should be normalized to equal surface, such that a flat light spectrum results in lms=(0.33,0.33,0.33), or a 6500 K color temperature in (0.313,0.329,0.3582). Especially the S spectrum needs a significant scaling. That also means that you'll need to prevent overflow/underflow (RGB values must be within 0..255 range). I'm actually not sure why that isn't a problem now; 410 nm will give something like LMS=(0.24,0.01,0.01). After your matrix multiplication, that would result in G=-0.25. On my computer (linux/glibc-2.3), pow(-0.2,0.4) will return NaN. NaN times 255 and converted to unsigned char happens to be 0 on my computer, but I wouldn't consider that an elegant way to deal with colors that cannot be reproduced in RGB. ;)

You have a very, uhh, compact way of programming. I stopped coding like that after a few occasions where I had no clue what the code did after a few months. ;-) The cosine is to make a fuzzy top border, I presume. (Why?)

Han-Kwang (talk) 13:13, 4 May 2004 (UTC)

The fuzzy border was just to look pretty.

The background isn't actually black, that's why there aren't any negative numbers causing problems.

I'll try integrating the spectrum and normalizing in a while. Κσυπ Cyp   13:31, 4 May 2004 (UTC)

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By now I am utterly confused. I think that the matrix I provided was not correct; it transformed from RGB to xyz, not to LSM. The normalization condition applies to the xyz coordinates. I still don't grasp what the xyz coordinates represent. I remember from my course in human color vision the phrase "The CIE diagram seems to be designed to confuse beginners in the most thorough way, but once one gets used to it, it is actually quite convenient". Once this gets sorted out, quite a few Wikipedia pages will need rewriting (dominant color, color, CIE, gamut). :-( Han-Kwang (talk) 14:07, 4 May 2004 (UTC)

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I've just rescaled, so the proportion of L, M and S should be correct now. (At least, before being multiplied by the matrix in question...) I also scaled the values, so they are within the correct order of magnitude instead of overflowing so they coincidentally look almost right...

Control+Shift+click-on-reload might be required to reload the images in crazy browsers. Κσυπ Cyp   16:20, 4 May 2004 (UTC)

Just looked at a link above, and it says x=X/(X+Y+Z), y=Y/(X+Y+Z), z=Z/(X+Y+Z). Doesn't seem as if X, Y and Z are L, M and S, either.

So I suppose what I need to know is what the relative L, M and S stimulus values are for some well defined spectrum (such as E/dλ=constant for wavelength λ>0 and E/dλ=0 for λ<0 or such as E/dω=constant for frequency ω>0 and E/dω=0 for ω<0 - if it's the second, I think I would need to divide by a factor λ² before integrating), and also, in the same L, M and S system, a matrix to transform between R, G, B and L, M, S, where R=G=B=1 is the brightest a typical monitor can show...

(Tried searching the internet, but all I can find is sites that have copies of Wikipedia pages...) Κσυπ Cyp   18:38, 4 May 2004 (UTC)

---

I'm deuteranopic (I think) and the spectrums normal and deuteranopia seem different to me. In the normal one, there is a clear red (this is much clearer than the kind of red that I can't distinguish from green) while it seems to me that there is no red on the deuteranopic. The deuteranopic and protanopic spectrums seem nearly the same to me, only the protanopic is shrinked (I don't know why it's shorted, it might be that I don't see the latest part or it's really shorter). Hope it helps in some way.

Note that all the images I've seen for doing such comparisons are rather a real images (photos) converted to these palletes. I have given a link above. Maybe it's easier to compare spectras for the brain or something and I can distinguish them even if I wouldn't distinguish them so clearly in a real picture. Or your algorithm is just plain wrong. I really can't tell, I can only tell what I see.

The more I think about it, the more difficult it seems to create a good test for this.

 --hhanke 21:50, 4 May 2004 (UTC)

---

I think I'm starting to grasp it, after some studying of the CVRL pages. The problem with all these different color-matching functions (CMFs) is that it impossible to measure the cone spectra directly. The XYZ quantities from the CIE diagram are closely related to the empirical data, and dependent on the measurement procedure (field of view, hence the 2 deg and 10 deg variants; test persons; light intensity, etc.). From a measurement, one can estimate cone spectra. The cone spectra from the above website (10 deg, Stiles/Burch) are a linear combination of the XYZ CMFs (from CIE 1964). The following matrix converts XYZ to LMS (the tabulated values, without further normalization):

XYZ2LMS =
    2.2286e-01    8.3347e-01   -3.8906e-02
   -4.2965e-01    1.1990e+00    9.6003e-02
    4.6299e-04   -1.1542e-03    4.9692e-01

and the inverse:

LMS2XYZ =
    1.9174e+00   -1.3325e+00    4.0755e-01
    6.8710e-01    3.5638e-01   -1.5056e-02
   -1.9053e-04    2.0693e-03    2.0120e+00

I constructed these matrices by comparing the XYZ and LMS values at 450, 550, and 650 nm, and the CIE 1964 CMFs give the best fit (compared to CIE1931 and corrected CIE1931). I leave it now to Cyp to write a new version of his program that, finally, adequately converts the LMS values to computer RGB values. Note the difference between the above XYZ (uppercase) coordinates and the normalized lowercase xyz coordinates. The Poynton Color FAQ lists the following conversion matrix from RGB RGB (on a CRT, white D65) to XYZ:

RGB2XYZ =
  0.412453 0.357580 0.180423
  0.212671 0.715160 0.072169
  0.019334 0.119193 0.950227

You'll probably need to scale LMS to get RGB into the range 0..1. I probably did something wrong again; RGB=(1,0,0) gives negative LMS values. But I think it's time for a sleep now. :-)

I read somewhere in either the FAQ or the CVRL pages that although a CRT should produce a 6500 K color temperature, in practice they often are 9500 K (too much blue). One may wish to fudge down the blue component in order to get a compromise that more-or-less works on both 6500 K and 9500 K displays.

Does anyone have a suggestion on which page we can put all this stuff about CMFs and cone functions? It's too technical for color and color blindness. Maybe on CIE?

Han-Kwang (talk) 23:40, 4 May 2004 (UTC)

---

Trying to use the LMS and XYZ data, I got a slightly different XYZ->LMS matrix, maybe I was looking at a different page. Here are the matrixes I used. (I used the RGB->XYZ matrix given above.)

                A
   450       550       650
L .0498639, .940198,   .16141
M .0870524, .977193,   .015448
S .955393,  .00195896, 0
 
               B
     450      550      650
X .370702, .529826, .268329
Y .089456, .991761, .107633
Z 1.9948,  .003988, 0
 
              XYZ->LMS=AB-1
        X                 Y                  Z
L  .2814879424,      .7978837522,     -.0630939103
M -.42961038,       1.214543157,       .0690102539
S -.00002518893483,  .00006279599838,  .4789436134

Here is the version of the program I used. I won't try to merge it with the above version (might miss some changes while merging), so it might be hard to read... Contains some dead code.

#include <math.h>
#include <stdio.h>

unsigned char asdf[54], rgb[3];

/*double mat[3][3]={
{1.768472906,  -.7931034483, -.3004926108},
{-.8177339901, 1.908045977,   .1018062397},
{ .0492610837, -.1149425287, 1.198686371 }};
*/
/*double mat[3][3]={
{ 2.088353414,  -.9906291834, -.3212851406},
{-1.155287818,  2.236055332,   .0495314592},
{  .0669344043, -.245426149,  1.271753681 }};
*/
/*double mat[3][3]={
{4.783887884,  -4.408367044,   .2244948933},
{-.5422530806,  1.900847365,  -.2585584114},
{-.0293065676,  -.1488607757, 2.225178275 }};
*/
double mat[3][3]={
{5.157293474,  -4.866693366,   .3407510271},
{-.5694932273,  1.960161505,  -.3396528051},
{-.0336993532,  -.1446765756, 2.153031303 }};

double table[441][3];

double unused;

int zero=0;

int main() {
  FILE *i, *o;
  double R, G, B, L, M, S, f, g,//ll=0,mm=0,ss=0,
  ll=.1296229615,mm=.1156955995,ss=.0698320795,
  //ll=.0377025928,mm=.0150533162,ss=.0236552135,//ll=0*.0274029192,mm=0*.0122894124,ss=0*.0222623102,//ll=.0893632596, mm=.0797616083, ss=.0481428766,//ll=.0712274589, mm=.062982337, ss=.0372662419,//ll=.0241, mm=.011, ss=.021,
   rng[9]={1,1,1,0,0,0};
  int x, y, error=0,best=1323,besty;restart:error=0;
  if(!(i=fopen("c:\\projects2\\spectrum.bmp", "rb"))) {printf("File not found.\n");return(0);}
  fread(asdf, 54, 1, i);
  fclose(i);
  if(!(i=fopen("c:\\projects2\\ss10e_1.txt", "rt"))) {printf("File2 not found.\n");return(0);}
  for(x=0;x<226;++x)   fscanf(i, "%lf,  %lf,  %lf,  %lf", &unused, &table[x][0], &table[x][1], &table[x][2]);
  for(   ;x<441;++x) { fscanf(i, "%lf,  %lf,  %lf,",      &unused, &table[x][0], &table[x][1]); table[x][2]=-1e99; }
  for(x=0;x<441;++x) for(y=0;y<3;++y) table[x][y]=exp(table[x][y]);
  //for(x=0,L=M=S=0;x<441;++x) { L+=table[x][0]; M+=table[x][1]; S+=table[x][2]; } //Integrate
  //L=1/L; M=1/M; S=1/S; f=(L+M+S)/3; L/=f; M/=f; S/=f; //Correct proportion, but keep overall intensity about the same (otherwise image would either appear black, or so bright the computer screen catches on fire (at least, if it didn't overflow first...))
  //for(x=0;x<441;++x) { table[x][0]*=L; table[x][1]*=M; table[x][2]*=S; }
  fclose(i);
  o=fopen("c:\\projects2\\spectrum.bmp", "wb");
  fwrite(asdf, 54, 1, o);
  for(y=79;~y;--y) { if(y<20) f=0; else if(y<30) f=1-cos((y-20)*(3.1415626935897932384626433832795/10)); else f=2; for(x=0;x<441;++x) {
    //L=table[x][0]*.3127; M=table[x][1]*.329; S=table[x][2]*.3582;
    L=table[x][0]/5.; M=table[x][1]/5.; S=table[x][2]/5.;
    L*=f; M*=f; S*=f;
    x+=390;
    if(y>=55&&x%  5) L=M=S=0;
    if(y>=60&&x% 10) L=M=S=0;
    if(y>=65&&x% 50) L=M=S=0;
    if(y>=70&&x%100) L=M=S=0;
    if(y>=75&&x%500) L=M=S=0;
    x-=390;
    //L+=.615; M+=.615; S+=.615;
    //L+=.5+.05*exp(-(x-55)*(x-55)/5000.); M+=.5; S+=.5-.05*exp(-(x-55)*(x-55)/5000.);
    //L+=.3+.05*exp(-(x-55)*(x-55)/5000.)+.2*exp(-(x-100)*(x-100)/50000.); M+=.3+.2*exp(-(x-100)*(x-100)/50000.); S+=.3-.05*exp(-(x-55)*(x-55)/5000.)+.2*exp(-(x-100)*(x-100)/50000.);
    //L+=.5; M+=.5; S+=.5;
#define sp(c,i,s) (i*exp((double)(x-c)*(double)(c-x)/(double)(s*s)))
    //g=.01+sp(55,.04,30)+sp(210,.01,60);//sp(45,.09,65)+sp(300,.01,100);//.015;//+.03*exp(-(x-55)*(x-55)/9000.)+.01*exp(-(x-105)*(x-105)/50000.);
    //L+=.009;//+sp(55,.0346/*.07*/,50);//+sp(210,.01,60);
    //M+=.009;//+sp(55,.0346/*.05*/,50);//+sp(210,.01,60);
    //S+=.009;//+sp(55,.0346/*.03*/,50);//+sp(210,.01,60);
    L+=ll;//.035;
    M+=mm;//.022;
    S+=ss;//.022;
//    L+=g;
//    M+=g;
//    S+=g;
    //L=      M*.95+S*.05     ; //Pro
    //M=L*.65      +S*.05     ; //Deu
    //S=L*-.1+M*1; //Tri (Very hard to get in range... Need to add exactly .028...)
      //S=L*-.77+M*1.86    +.028; //Tri (Very hard to get in range... Need to add exactly .028...)
//      S=L*(-.78+.2*(y/40/40.))+M*(1.75+.2*(y%40/40.))+.028;//L*-.2+M*0.7;//L*-.7+M*1.6      ; //Tri
//      S=L*-.77+M*1.86+.028;//L*-.2+M*0.7;//L*-.7+M*1.6      ; //Tri
    R=L*mat[0][0]+M*mat[0][1]+S*mat[0][2];
    G=L*mat[1][0]+M*mat[1][1]+S*mat[1][2];
    B=L*mat[2][0]+M*mat[2][1]+S*mat[2][2];//R=L;G=M;B=S;
    //R/=.2120267738; G/=.3921458724; B/=.3957273539; //Scaling so LMS(.3127,.329,.3582)==RGB(1,1,1)
#define dr(x) {x rng[6]=L; rng[7]=M; rng[8]=S;}
    if(R<0||G<0||B<0||R>1||G>1||B>1) { ++error; }
        if(R<rng[0]) rng[0]=R; if(G<rng[1]) rng[1]=G; if(B<rng[2]) rng[2]=B;
        if(R>rng[3]) dr(rng[3]=R;) if(G>rng[4]) rng[4]=G; if(B>rng[5]) rng[5]=B;
        if(R<0) R=0; if(G<0) G=0; if(B<0) B=0; if(R>1) R=1; if(G>1) G=1; if(B>1) B=1;
        
    if(R<0||R>1) R=((x^y)&2)/2; if(G<0||G>1) G=((x^y)&2)/2; if(B<0||B>1) B=((x^y)&2)/2;
    R=pow(R, .4);
    G=pow(G, .4);
    B=pow(B, .4);
    rgb[2]=R*255.; rgb[1]=G*255.; rgb[0]=B*255.;
    fwrite(rgb, 3, 1, o);
  } fwrite(&zero, 1, 1, o); if(best>error) {best=error;besty=y;}/*Dumb rounding line length up to 4 bytes...*/ }
  fclose(o);
  if(error) { printf("Warning: Out of range.\n"); } //else { rr-=.0001; goto restart;}printf("%lf\n", rr+.0001);
  printf("Range:\nRed:   %lf to %lf\nGreen: %lf to %lf\nBlue:  %lf to %lf\n", rng[0], rng[3], rng[1], rng[4], rng[2], rng[5]);
  printf("LMS: %lf, %lf, %lf\n", rng[6], rng[7], rng[8]);
  //for(x=0;x<441;++x) printf("%d, %ld, %ld, %lf
}

How do the following images look now, after reloading the page and images? (Control+Shift+click-on-reload, perhaps.) (The regular spectrum looks better to me now, there seems to be violet at the left end.) Κσυπ Cyp   12:27, 5 May 2004 (UTC)

← Regular

← Protanopic

← Deuteranopic

← Tritanopic

---

I've not yet looked at your code, but the uppermost picture looks very realistic, although the yellow/orange band seems a tiny bit too wide - I built myself a toy spectrometer out of a piece of compact disc and cardboard, so i know what it approximately should look like, although it doesn't have a wavelength scale. A few reference wavelengths:

• 632 nm (He-Ne laser) should be bright red, but is shown as orange. Actually the whole red part of the spectrum seems too orange-like.
• 590 nm (sodium street lighting) should be yellow/orange (approximately as it is at 600-610 nm in the current figure), but is now yellow/green.
• 514 nm (argon laser) should be hard green, seems alright here.
• 400 nm looks good.

The eye is most sensitive to the wavelength around 600 nm (transition from red to green). My impressions may be affected by the reddish background color that you used in order to prevent negative RGB values. Didn't it work out with a dark grey background?

The difference between your and my matrix is that you used the 2-degree cone fundamentals instead of the 10-degree. The angle refers to the field of view; the yellow spot (macula) on the retina obviously affects the color perception to some extent. If you use your conversion matrix, then the converted xyz CMFs and the LMS CMFs do of course exactly match at 450, 550, and 650 nm, but at other wavelengths, especially between 440 and 540 nm, they are a bit different. (With CIE1931 instead of CIE1964, it's even worse). Hence, I recommend to use the 10-deg LMS table together with the CIE1964.

Han-Kwang (talk) 13:33, 5 May 2004 (UTC)

---

If I'm (as a deuteranopic) supposed to see the normal and the deuteranopic spectrum the same, this is still *not* the case. The normal is clearly red on the right while the deuteranopic isn't. I feel sorry that I'm not able to help you with the math and I can only provide a description of what I see :( Also, it might be of interest to you that I have severe problems distinguishing the red links on wikipedia (normal, not visited) from the green ones (the article doesn't exist) (just for reference, this isn't a problem in Wikipedia as I can solve it easily by leting it display the question marks instead of green links). I'm using galeon with the default Wikipedia skin. --hhanke 20:03, 5 May 2004 (UTC)

I've used the 10° data completely now, not using any 2° data. Doesn't seem much different, but who knows... I've re-uploaded the images, again...

Having a grey background requires a rather bright background compared to a having a purple background. The orange on the attempted deuteranopic image might be very slightly brighter now, but I'm not sure.

← This one still has gamma 2.5. Κσυπ Cyp   23:09, 5 May 2004 (UTC)

This image should have an equally easy to see (and equally hard to read font) 'pro', 'deu' and 'tri' written on it. Κσυπ Cyp   23:15, 5 May 2004 (UTC)

Deu is still visible for me. I liked the images with non-connected surfaces much better. You could try to convert it to that stile. --hhanke 16:09, 6 May 2004 (UTC)

Pro is not visible to me (protanope). --Chinasaur 04:27, 30 Sep 2004 (UTC)

---

My monitor has gamma 1.5, not 2.5. What gamma do other people have? (See image at gamma correction to check.) I changed the gamma of the images to 1.5 and reuploaded them. Κσυπ Cyp   22:50, 16 May 2004 (UTC)

← Here's one with gamma 1.65.

File:Colorblind3.png ← Gamma 1.65, supposed to test for protanopia...

File:Colorblind4.png ← Gamma 1.65, supposed to test for deuteranopia...

File:Colorblind5.png ← Gamma 1.65, supposed to test for tritanopia...

File:Colorblind2.png ← Gamma 1.65, supposed to test for complete blindness...

I want 1.92 γ for my Powerbook G4. lysdexia 14:48, 22 Nov 2004 (UTC)

---

Great! I don't see anything on the deuteranopic image (and I'm supposed to be deuteranopic)! I think this is the best test for deuteranopia from the ones offered here. I can see the other two, but these are for other ilnesses. So if the seccond image is clearly visible to you but invisible to me, great! Please could you additionally make a reference image in some by-all-distinguishable (by all I mean even by monochromatic people) colours (I mean for example blue-yellow) in the same stylo to accompaniate these real tests? --hhanke 07:24, 19 May 2004 (UTC)

I am protanopic and cannot see the first number at all. The second number is difficult to make out, but I got it eventually. Feel free to post to my talk page if you have any more protanope testing needed. The spectrum is also working for protanope me. Not sure what gamma I have set. --Chinasaur 04:23, 30 Sep 2004 (UTC)

The three (now four) images appear approximately equally clear to me. Although I can't guarantee that the new one can be seen by people with only one colour cone, it is intended to be seen by everyone. (At least, by everyone who isn't actually blind, not just colour-blind.

For reference, the numbers are supposed to be , , and . (Click 'edit this page' and read backwards to read the numbers.) Κσυπ Cyp   09:00, 19 May 2004 (UTC)

Note to self, for future creation of these images:

Corel photo-paint 9
Solid fill, 50% black
Effects/Noise/Add Noise:Gaussian, Level=100, Density=100, Color mode=Random
Effects/Blur/Gaussian blur: Radius=I think about 2 pixels...
Draw something on a colour channel: Paint mode=add, Nib=Round-30px, Soft edge=100, Anti-aliasing=on-smoothing=10, Dab-spacing=25 (ratio for #83: 43/70/120)
Draw on mask: Texture fill: Vapor 2C, #=11257, Softness=50, Density=0, Brightness=0, Background=black, Vapor=white
Invert mask
Solid fill, 30% black
Save, use program

--- Good, but the last image (the one that should be easy for everyone is harder for me than the protanopic one for example). Maybe you could do it even easier. This doesn't test for anything, so it doesn't have to be too close to the other ones, in my opinion. Just for reference, so that everyone knew he's looking for some number and it's displayed in such and such way. This is at least how these reference images in the tests use to be. Very clear, just to see what I'm looking for. But anyway, great work.

Just one more hint. Please forgive I'm bitching about the very good work that you are doing here and I'm not able to help you. I think it would be better to use simple geometry figures (like a star, a square, a triangle, a circle) instead of numbers. The reason is that you can test even small children that don't know the alphabet and the numerals yet. I've seen somewhere this point as a critique against the (still widely accepted) Ishara tests.

I had the idea that maybe I could ask our doctor to test these images against other people who she diagnoses with colorblindness based on some other (official) tests. It doesn't require much from her, just to show one or two more pictures. I think she might understand our good intentions. This way, we could get feedback (hopefully approval) of more people. I have yet to figure out how to print the images with the correct gamma factor though. --hhanke 15:22, 19 May 2004 (UTC)

Red-Yellow-Green

If yellow is a mixture of pure red and pure green, but red-green color-blindness allows both red and green to look gray, does this allow red-yellow-green to become gray-yellow-gray or gray-gray-gray?? 66.245.6.12 00:03, 25 Aug 2004 (UTC)

There are different forms of red-green color blindness (see the article), but essentially any red-green deficiency will also cause trouble in distinguishing yellows from greens and reds. However, what happens to make these colors mixed up is not as simple as just turning them all gray. Normal trichromatic vision is based on opponent processes (try googling it): basically any physical light spectrum input is degraded (in normal vision) into two simple color dimensions: "how red versus green is it?", and "how blue versus anything else is it?". So perhaps in red-green color blindness you simply lose the "red versus green" dimension, and now all the complicated light spectrum input is being degraded into only one color dimension: the "blue versus anything else".

This might be true, but cannot be a complete description of the deficiency, because there is further loss of information even before the opponent process level (e.g. someone lacking the red cone will mix up blue and purple, although this would be detected with only a "blue versus everything else" opponent process). The best way to understand the pre-opponent-process deficiencies is from the perspective of photoreceptors and copunctal points (try googling it): if the red cone is missing, then addition of light spectra that would normally stimulate that cone will not be noticed. So if you add some red light to some blue light, making purple for normal vision, someone missing the red cone sees only blue. --Chinasaur

(This discussion has focused on color processing, so we have ignored the third dimension of information, the brightness of the light, but this does not affect perceived color very much.)

Explaining dichromat perception to the layman

Here is a summary of the points of agreement coming out of this dispute that basically boiled down to: "how should we best explain the experience of a dichromat or other color deficient to a layman trichromat?". For simplicity all specifics in this summary are stated in terms of protanopia. Many of these points have been made before, but at least this is shorter than trying to read the whole argument...:

1. To a layman, the easiest way to explain a dichromat's experience is in terms of what colors will be confused: "Purple appears the same as blue", "green appears the same as yellow", etc. These are important points to make to avoid common misconceptions such as that a red-green colorblind person simply sees gray in the place of red and green. There are additionally two more complicated ways to address this:
   1. Getting into what a dichromat actually sees, e.g. "only in white, black, blue, and yellow". This question is a natural extension of describing what a dichromat confuses, and is interesting to many laymen. However, what a dichromat actually sees cannot be determined with certainty, and the existing data are not easy to explain (especially not compared to the simplicity of the areas of confusion data). Much of the explanation of the higher perception of color to a dichromat is based on opponent process models. We can tell that the opponent process argument has merit because it agrees to some extent with personal reports from unilaterally color blind individuals. But it is more complicated than the standard blue-yellow, green-red opponency model would suggest, and we can not be fundamentally certain that unilateral color blind accounts bear on dichromatic experience ([2]). This is worth getting into once the initial simple description of what is confused is out of the way.
      • One point is that around the neutral point, there are monochromatic stimuli that are colored in trichromats but appear gray to dichromats. However, as noted above, this does not mean that red-green color blind individuals see only gray in place of red or green. A better analysis is that dichromats replace much of the hue discrimination of trichromats with color saturation gradations.
   2. Getting into the details of color blindness at the photoreceptor level: metamerism, copunctal points, just noticeable differences. This is the nitty-gritty of exactly what will be confused. Photoreceptors determine what input goes into opponent processes and higher perception. Much of it can be covered in other articles and linked, but it should be covered.
2. We should discourage (as is already done) the misleading association of color names with wavelengths, spectra, or even particular human cones. We must be careful our language is rigorous when writing in the formal article. There are three levels of distinction important in the discussion of color transduction:
   1. The physical level, in which we talk about frequencies, wavelengths, spectra, etc.
   2. The high perceptual level, in which we use color names. At this level we can say that yellow has nothing to do with red and green; it has no redness or greenness to it. It makes no sense on a perceptual level to describe yellow as greenish-red.
   3. The photoreceptor level. This must be distinct from the physical level since information has made a huge shift from a myriad of physical light spectra into simple tristimulus values. However, it must also be distinct from the high perceptual level, in which tristimulus values are further transformed into opponent process information. The best language for this level is LMS cones, not the traditional language of RGB cones. RGB cone terms are too easily confused with the names of actual colors, which exist only at a higher peceptual level.
      • This is the source of many linguistic ambiguities, such as "red and green make yellow". An accurate, rigorous rewording is that in trichromatic primates (at least humans and macaque as far as I know), a particular ratio of L and M cone stimulation (without "significant" S cone stimulation) will lead to a peception of yellow through opponent processes. However, the popular idea that "red and green make yellow" probably stems from light mixing demonstrations, in which combining any light spectrum that humans peceive as red with any light spectrum that humans perceive as green will result in a light spectrum that is perceived as some shade of yellow (possibly beige or brown depending on the saturation/brightness). (This is a direct result of the LM cone argument.)

Summary modified/created by:

1. Chinasaur 20:42, 5 Oct 2004 (UTC)
2. Chinasaur 04:35, 6 Oct 2004 (UTC)

Hear, hear. Especially point 2. There are essentially no popular explanations of 'color' that keep these things straight like they ought to, and it makes a mess of things (as evidenced even by some of the questions that get asked on this very page. Let's make Wikipedia the first explanation of color not to suck. eritain 05:48, 16 February 2006 (UTC)

It's red and green, not blood and hunter. lysdexia 14:48, 22 Nov 2004 (UTC)

Hm...

I am not color-blind (always passed the tests OK) but I have some difficulty seeing clearly the second digit of Gamma 1.65, supposed to test for deuteranopia. The shape seems to be rather irregular...

Question

A person with a red/green defect will confuse green for which color? White, Red, Blue, or Yellow

And what will they confuse red for?

It depends on what type of red/green deficiency is present. The confusion lines on the plots here: [3] indicate which colors tend to be confused by protanopes and which by deuteranopes. All colors along the lines will tend to look the same hue to the color blind person. If you are not familiar with the horseshoe shaped color space, see International Commission on Illumination; the image there should help you figure out which colors the lines are running over. --Chinasaur

Image subtitles

The images on the article's page should be subtitled what number a normal-seeing person sees, and what color-deficient persons see. --Abdull 11:00, 23 Mar 2005 (UTC)

I disagree. The test would be meaningles if everyone knew what should they see on it. It's much easier to recognize (or maye yourself think you recognize) a number if you know it in advance. The principle is explained well (even giving the numerical value 83) in the first sample image. --hhanke 19:07, 24 Mar 2005 (UTC)

Moreover, if you click on the images, you get the number a normal-seeing person sees. --Celsius

Either my monitor is pretty bad or the images aren't really great.

OK, i'm not colorblind as i've had atleast a couple of different tests online and offline. but the article, especially the 3rd image is dubious. Now it could be my monitor, but the fact is i can make out that the first number is 4, but the second number is where the confusion steps in as it looks like the numbers 1, 4, 7 and not 9. More to do with fuzziness than with color blindness. I suggest that this image is to be improved as a few others i know who are normal have said the same thing when i gave them the "test" on my PC. Other online tests are 100% accurate and they include the ishihara color blindness test.--Idleguy 14:16, Jun 18, 2005 (UTC)

That one's iffy. If you got that first 4, and can see the second digit at all, you're fine. The second digit is definitely not clear. If someone has access to a different image, great, otherwise, I think we just need to deal with it. Maybe add a note about that one being fuzzy in the caption. -- Dpark 04:42, 23 Jun 2005 (UTC)

Blah, I went ahead and just added the note myself. If we get a newer image, we can always remove the note. -- Dpark 04:48, 23 Jun 2005 (UTC)

---

I agree with this. I'm not colorblind and never have any trouble seeing the numbers at the optometrist's, but I could barely make out the numbers in these images (except 37). It took me a while to realize the last one was 56 (right?). Colorblind people do not need such ridiculously undersaturated colors to not see them.

Green yellow and greenish yellow

"their peak sensitivities in the blue-violet, green-yellow, and greenish-yellow regions of the spectrum, respectively"

This excerpt from "Causes of color blindness" doesn't make any sense. Green-yellow and greenish-yellow? I am not very knowledgable about this subject, but I hope that someone else can fix this.Apatterno 04:46, 7 August 2005 (UTC)

yes, that was pretty good nonsense. Someone trying to correct a phrasing they hadn't read properly, and then being pedantic about the colours. I've fixed it for now, but I don't guarantee it won't get messed up again; this is a subject on which schoolchildren (and not only schoolchildren) are taught with great confidence entirely bogus information, so it is susceptible to mis-editing by people who believe in good faith they know what is going on, but don't. seglea 17:39, 8 August 2005 (UTC)

Monochromacy rate of Pohnpei

This article originally stated that roughly 1/12 of the population of Pohnpei suffers from achromatopsia; in actuality, it is the island of Pingelap, which is located 180 miles from Pohnpei and is a part of the Pohnpei State, that has this rate. --Marco Passarani 05:14, 21 August 2005 (UTC)

Cure!

Ah.. were did you read about this? Color blindness may be a result of many different causes. But I have a hard time imagining how genetic color blindness may be cured. Can you cite references? Fred Hsu 02:37, 30 May 2007 (UTC)

There's a recent AP article he may be talking about. Looks like it's a retrovirus that may be used to treat achromatopsia. --Xanzzibar 04:43, 30 May 2007 (UTC)

Yes, I have heard of a cure too! I also hear it works!!!--Mary divalerio 16:57, 7 September 2007 (UTC)

Other color deficiencies?

The article as is only addresses the classic definitions of color deficiencies. There's nothing wrong with that, but should it also include other color deficiencies or should they be in a separate or alternate article? Specifically, I'm thinking of the common age-related color deficiency do to the yellowing of the lens, and also the forms of low-light color deficiency (which I'm not very familiar with). --Ronz 20:46, 29 November 2006 (UTC)

I'm trying to research the colorblindness that I suffer from, but I can't seem to find it. To my knowledge, I can see every color, but similar colors are very difficult for me to distinguish when next to one another, and certain colors, when I view them on their own (brown, red, green, grey and some shades of blue, for example), I can't tell what color it is at all. Does anyone know what kind of colorblindness this is? --Steam Giant 12:53, 16 March 2007 (UTC)

NooOoo... I didn't suspect that it was colorblindness... ... said: Rursus (^mbork³) 18:19, 27 October 2009 (UTC)

Heredity

The article says, in regards to being a

Genetic red-green color blindness affects men much more often than women, because the genes for the red and green color receptors are located on the X chromosome, of which men have only one and women have two. Such a trait is called sex-linked. .... In turn, a carrier woman passes on a mutated X chromosome region to only half her male offspring.

This is going to sound like hair-splitting but is this sort of... inaccurate? It is possible for a carrier woman to have no colour-blind male offspring or even 100% of male offspring colour-blind. It's just that statistically she will have a 50% probability of having a colour-blind son, because it's the chance of which X chromosome will be present in the zygote at conception. That means if she only has one son, it's 50-50 if he's colourblind, so the result would be either 0% or 100% colour blindness in male offspring... you get my point. I'm pretty sure this is right, but I could be wrong. If not, could someone change it so maybe kids learning about heredity don't get confused? - spider84 (password problems, can't log in) 220.237.244.200 09:10, 3 December 2006 (UTC)

You are exactly correct, and you're not hairsplitting (in my opinion, anyway). I updated the text to: "In turn, a carrier woman has a fifty percent chance of passing on a mutated X chromosome region to each of her male offspring." – Zawersh 21:13, 18 April 2007 (UTC)

Regarding the Sample Images

For reference, following are the removed images that are referenced in this discussion. -- – Zawersh 13:04, 25 April 2007 (UTC)

• This is a sample image. The pictures below should look similar to people with normal vision (containing numbers, in this case 83), but some of them will not be visible to people with a color vision deficiency. The contrast in these tests is much subtler than commonly seen in other similar tests.
  This is a sample image. The pictures below should look similar to people with normal vision (containing numbers, in this case 83), but some of them will not be visible to people with a color vision deficiency. The contrast in these tests is much subtler than commonly seen in other similar tests.
• This image contains the number 37, although someone who is protanopic might not be able to see it.
  This image contains the number 37, although someone who is protanopic might not be able to see it.
• Someone who is tritanopic might not see this number (56).
  Someone who is tritanopic might not see this number (56).

I've expanded the note to make it clear that these images cannot be used to test for color blindness on a computer display. Color-blindness tests are valid only when given in person under the controlled conditions required by the test. Even the best color monitors are not satisfactory for this purpose (you would need a calibrated monitor, a special viewing environment, and a test specifically designed for use with the monitor for that), and readers must not be given the impression that they can test themselves for the presence or absence of color blindness using the images in this article. Agateller (talk) 15:03, 15 August 2009 (UTC)

Those images tend to be more visible on a monitor set to a lower level of brightness than on one set to a higher level of brightness. I find this quite misleading. —The preceding unsigned comment was added by 24.84.41.35 (talk) 04:40, 11 December 2006 (UTC).

They're useless on an LCD, so I've removed them from the article. boffy_b 08:22, 17 January 2007 (UTC)

Should we remove images that are fine for readers with better quality monitors? They still give all readers an idea of what the tests are like no matter the monitor quality. --Ronz 17:10, 17 January 2007 (UTC)

Actually, they are only useless when the LCD isn't used in its native resolution, but it can be told to the users. I think they could be kept. Thomas Bertels 16:08, 18 January 2007 (UTC)

I'm slightly colour-blind (and it IS COLOUR, as my goddamn english teacher keeps telling me), and i think these images are only accurate for people wha suffer from strong-colour blindness. and how do people get these images, as you cannot see out of another person's eyes? i do not see how you would tell that green looks very blue to some people. -Grim- 00:27, 16 March 2007 (UTC)

It may be worth noting that these images and many others were discussed (now in the archives) before they were used (and at times removed). See Removed images, Color blindness test, Cone fundamentals and generating a spectrum, Either my monitor is pretty bad or the images aren't really great., What I see, Spectrum picture. Also see below, Rainbow Errors?. Every time a set of sample images get put up, they get pulled down several months later because someone doesn't like them.

We seem to be trying to fill three illustration needs with the various images proposed and used for this article over time: show what a colorblindness test looks like, simulate colorblindness for a non-colorblind person, and actually test for colorblindness. The last criterion is impossible to achieve. This is not a testing facility, and with monitor variations and individual colorblindness variations, we will never have an image test that works properly. So let's discard that one.

To show what a colorblindness test looks like, we should use an actual real world colorblind test, preferably one that's widely used. This makes the images in Ishihara color test good candidates. I don't think we should not make up our own colorblindness tests because those aren't illustrative of real colorblindness tests. And I also don't think it matters if the image we use actually tests colorblindness when displayed on a monitor -- it's there to show what the test looks like, not to actually test anything. I'm going to re-add an Ishihara image to the article for now.

To illustrate colorblindness by way of simulation, the flags that are currently in the article work just fine. They show what a set of colors might look like in various forms of colorblindness, which gives non-colorblind people (and even colorblind people with other forms of it) some idea what happens with those kinds of colorblindness. Do they match up perfectly with my or someone else's colorblind eyes? No, but they don't need to, either. They'll illustrative, and they're never going to match any one person's eyes perfectly.

I personally think that the grey background images that were removed (now shown above) weren't very good. They don't illustrate any common colorblindness tests, and they don't simulate colorblindness for a non-colorblind person very well. I don't think they should be re-added. – Zawersh 13:31, 25 April 2007 (UTC)

They're a lot better than the ones we have now. The ones we have now aren't common ones with the rainbows, and the ones up there are better, we could just leave a note saying that those with the low frequency monitors or whatever won't see it. --64.205.199.7 14:18, 14 May 2007 (UTC)

I agree. We could just leave a note, I'm color blind (I'm sure the rest of you are, not to make myself feel special) and I find the one in the middle interesting considereing I cant see a bloody thing. --SurfingMaui540 23:19, 14 May 2007 (UTC)

I agree. I find it pointless that we would leave those ones in the article now. --LtWinters 21:29, 15 May 2007 (UTC)

Obviously, we all want it changed. I'm moving it back in. --LtWinters 22:59, 15 May 2007 (UTC)

No, we all don't want it changed back. If that were true, it wouldn't have been removed in the first place, and I wouldn't have voiced that I agreed with the removal.

You're each saying you think the grey-background images are better. Could you please clarify: what are they better for? They don't illustrate any real colorblindness tests. They don't simulate colorblindness. What point, exactly, do these images serve, and why do you feel they are better than the flags? I'm not exactly opposed to having them in there -- but I'm really not seeing that they add anything either, and I'm somewhat mystified that you all are so strongly advocating them. – Zawersh 07:06, 23 May 2007 (UTC)

Well, I think a lot of people wonder what people who are color blind do or don't see, and images that say "Someone with ___ can't make this out" are as helpful as ones that say "This is what ___ looks like to those with ___". To that end, I think both sets of images do serve a bit of a purpose, and it's nice to have a few more images to break up big blocks of text. I'd rather have images that are more in line with the picture at the end of the article (the tri/dichromat apple comparison), as I find that to be the most illustrative of how the condition affects real situations, but I think the other pictures do still add something. --Xanzzibar 13:16, 23 May 2007 (UTC)

I agree with Xanzzibar. I appreciated it for that reason (it is a valid test if not a commonly used one), and I'm sure people who are actually color blind (don't tell me they're irrelevant) would appreciate it even more. I have normal color vision and could easily make out the numbers on an LCD LUTted close to 1.8 gamma. The red 37 is blatant, the blue 83 slightly less so, and the purple 56 is faint but clear. Make sure you don't let colors clip by using broken brightness/contrast settings. If you do you voluntarily prevent colors from displaying correctly, and you shouldn't blame the image. A real problem with LCDs: without correction, whether done by the electronics in the monitor, the GPU, or software, the response curves tend to be rather weird.

Of course, if there's a quality replacement (that is, images with the same purpose) I don't mind; I'll leave that choice to the color blind or those who know how they are really perceived. --Jonathanvt 19:15, 23 May 2007 (UTC)

haha yes as I said.... most of us want it with those grey things...--LtWinters 18:57, 25 May 2007 (UTC)

• phew* and i thought i had all those diseases, when its just my lcd monitor. I can see 2 of the 3 numbers on the images here.(the Far Left and Far right). Seems a warning should be put on the image maybe to tell people that it may not work on a lcd screen. 219.88.78.200 20:25, 8 July 2007 (UTC)

Definitely. I was convinced I had tritanopia for a second until I tweaked the brightness. 86.137.77.251 03:21, 11 August 2007 (UTC)

My girlfriend and I viewed all three images on laptop LCDs. She said once she knew what she was looking for, she could see it: I still could not. Even after she traced it out. --76.243.28.8 03:57, 11 October 2007 (UTC)

These images suck. I'm not colorblind but they are way too subtle for anyone to reliably pick anything out from. What's wrong with the conventional high-hue contrast mesh of circles in a circle like this? --Belg4mit 16:40, 27 October 2007 (UTC)

I'm not colour blind, but on my laptop LCD, the 37 is clear, the 83 is hard to determine and the 56 is almost impossible to see. It's running at its native resolution, and even changing the brightness doesn't help much. -- Mithent 15:21, 10 November 2007 (UTC)

 Same here. #56 is junk. Find another.  —Preceding unsigned comment added by 75.42.82.54 (talk) 05:13, 3 December 2007 (UTC) 

I'm another voice saying the Triptanopia third test is useless. ( #56) The first and second tests, on a LCD screen, are very faint but the idea is clear, and the numbers are at least still visible. I can't see anything in the third one at all. It will send people off to their optometrist. I think it should be removed. --Trefalcon (talk) 13:24, 31 October 2008 (UTC)

I notice this discussion dates back to 2007, so there'as no guarantee that we're talking about the same images. However I have no difficulty with the Tritanopia test. I'm a borderline deuteranope (no problems with traffic lights) and I can't see the number in the Deuteranopia test. I now have an LCD monitor, but got the same results on a CRT. -- Philcha (talk) 13:52, 31 October 2008 (UTC)

I have normal color vision and can see the 56 on my laptop. (The angle of the screen seems to matter.) WhatamIdoing (talk) 01:19, 1 November 2008 (UTC)

Moved from article for discussion

Conversely, the board game Cosmic Encounter was designed and tested with colorblind individuals, and two of the player colors, a dark blue and a light blue, are difficult to distinguish by normally-sighted individuals.[citation needed]

I don't find the above notable. Isn't such testing commonplace? More importantly, hasn't this been a recommendation from design and human factors groups for many, many decades now? --Ronz 22:13, 21 December 2006 (UTC)

Speaking as a former program manager at a prominent software company, I can testify firsthand that testing for visibility by color-blind people is far from commonplace. I only wish it were more common.Conoisseur 08:38, 26 August 2007 (UTC)

Question for an expert

It is possible to possess both a protanomaly and a deuteranomly?Fistful of Questions 02:57, 29 December 2006 (UTC)

I would also like an answer. I can only see in the three basic colours, red, blue, green, and all mixed colours just look like the closest non-mixed colour, with the exception of some greens, oranges and browns (probably due to their very different brightness). I can't find this deficiency in the article, however I seem to be positive for both protanopic AND deuteranopic deficiencies. The test down the bottom, the circle of dots, I'm just going to say I can see both numbers, but very faintly.

So is it that it's possible to have multiple deficiencies, or one that's not on there or one I haven't read about yet? It's possibly my display, but I doubt it. I have taken tests before and know I come up with some strange results. ~Deadly-Bagel (talk) —Preceding comment was added at 13:12, 13 December 2007 (UTC)

my shot: protoanomaly and deuteranomaly are color vision diagnostic categories, not retinal photopigment genetic profiles. it is possible through analysis of an individual's photopigment genes to specify the exact chemical template for the L, M and S photoreceptors; this shows that both the L and the M photoreceptors exist in a handful of genetic variations. the variations are genetically independent, so both an L and M "anomalous" pigment can occur in the same person. the vision effects of the various possible combinations of L and M photopigment variants are complex and may or may not affect everyday color vision in noticeable ways. if a person takes a color vision test, the test results will be scored using standard criteria and the results classified into a standard diagnostic category. the usefulness of sticking a label on something always depends on what the label is used for. and that's a question that is rarely asked: what are the labels good for? —Preceding unsigned comment added by 67.142.161.23 (talk) 14:20, 7 June 2009 (UTC)

History

Dalton was NOT the first scientist to publish a paper on color-blindness. Specifically, there is a paper from the 1600s in the Transactions of the Royal Society (in the 1650s or 1660s. I think). I'll try to find it again and change the article. David Manthey 15:47, 22 January 2007 (UTC)

GA Class

Looking over this article, it appears to have everything that is required of a GA article and more. Da54 23:11, 17 January 2007 (UTC)

External links

I believe there has recently been an overzealous removal of external links. I have been reading this article and related ones on color perception in the past few weeks. I find these articles lacking real, hard information. In particular, I can't seem to find pointers and references to books accessible to the general public. Actual research papers are very hard to read for the layman.

In the process, I looked at many external links. Some are not very useful, and many of them are. I finally found a free software similar to what I was going to write. It changes the entire screen on a computer to make colors distinguishable for color blind people. The external page also includes detailed information on how it enhances images via saturation, filtering, color transaction and hatching. I added the link to this article and it was promptly removed among half dozen others.

I am going to add it back. If you plan to remove it, please look at the external page first to make sure you understand what you are doing. I don't immediately see how WP:NOT prohibits inclusion of this link. Removal of this link does a color blind person a disservice.

Unlike the unremoved link to www.vischeck.com, this external page is free of advertisement and the software is free. I installed it last night and it worked really well. Fred Hsu 16:25, 19 February 2007 (UTC)

• The link was: Visolve, free software that transforms colors, enhances saturation and redraws colors with hatches for color blind people. It comes with a standalone program to capture/transform images on screen and a toolbar in Windows taskbar to transform the whole screen.

WP:NOT#REPOSITORY: "Wikipedia articles are not: 1. Mere collections of external links." The problem is that the External links section is becoming a link farm of tools related to color blindness. The External links section should be supplemental information that supports the article topic WP:External_links#What_should_be_linked. Instead we have sections of external links on testing for color blindness, simulating color blindness, designing for color blindness, and tools to help people with color blindness. --Ronz 16:51, 19 February 2007 (UTC)

(If you don't mind, I'm going to change the title of this section to make it more civil.) --Ronz 16:51, 19 February 2007 (UTC)

I changed the title of this section. Can you please post your thoughts to talk page, before you re-remove links in the future? I plan to enhance this article after I am done acquiring and reading books on this topic. Perhaps I'll have more intelligent things to say about this topic after I write the program I siad I would write. Until then, some of these external links are extremely useful and are logical extensions for readers of the current article. If I found it very useful during my research, I think other reader will as well. Even after the rewrite, I think many of these external links are still useful. And, can you please answer my questions on www.vischeck.com? Why was the free software removed and this commercial page left? I am not advocating for removal of vischeck; I found it useful as well. But I don't understand the logic behind your removal. Thanks. Fred Hsu 17:04, 19 February 2007 (UTC)

Thanks. I tried to make the change and discussions at the same time. Sorry about not answering all your questions. I went through the links quickly and they certainly could be trimmed further. My basic perspective on this is that this is an encyclopedia, not a place to find tools and tests. --Ronz 17:39, 19 February 2007 (UTC)

I beg to differ with your approach. If we simply remove all unrefernced material and all external links from wikipedia, it will be extremely hard for people to gradually build up good articles over time. Instead, we leave stub templates, fact-check templates and notes in talk pages, with the hope that someone will come along and fix these problems. Please see [edit diff of Mitochondrial Eve] for an example. This article was full of incorrect statements and unreferenced statements. People could have simply removed all such problems, leaving the article with maybe two paragraphs. But instead, stubs and fact-checks were added and discussions started on the talk page. Eventually, someone thought it was time and rewrote the article.

You quickly went through links and removed those "you" deemed inappropriate. In the process, you probably removed some weeds and you also threw away jewels. Some good pointers useful for later editors are now gone. The external link section in wikipedia articles are really not part of the article. They are supposed to be pointers to readers who are not satisfied with the current state of the article. In time, they will become part of the wikipedia, with help from other editors.

As for tools, we live in the information age. Wikipedia is so much better than Britannica in part because it has interwiki links and external links to pages outside of wiki. After reading wiki article on Color Blindness, many reader would want to either try the dichromat experience or find software to help them cope with this condition. If they can't start their search here, where do they do that? Based on 'your' basic perspective, all links in external links section should be purged, because they are all links to tests and tools. Can you please explain 'how' you decided what to purge and what not to purge?

I am restoring the particular link I mentioned here. Please do not remove it unless you come up with better excuses. Thanks. Fred Hsu 19:52, 19 February 2007 (UTC)

Please be more civil in your discussion here and your edit summaries.

I'll remove items as I see fit, referring to the relevant guidelines when I do so.

It's the editor adding the material that is responsible for supporting it's use in the article. --Ronz 21:11, 19 February 2007 (UTC)

After my research, I may be able to write new articles on color blindness testing, simulation and tools which help color blindness people into separate articles. Then add sections in the Color Blindness article which point to these new articles. Until then, I believe these links should be kept in the external links section to help people expand this topic. Instead of simply removing all of them, you can also add cleanup templates or something to that effect. Or, create stub articles for these sub-topics and move links there. If you are simply reducing the number of links to some manageable set, I believe you need to be more careful with your selection of links (see my thought on Visolve vs Daltonize (vischeck). You can't just cite generic WP:NOT and WP:EL as reason for removal of this link, while not applying the same principles to all other external links. Fred Hsu 21:45, 19 February 2007 (UTC)

I went through all the links and removed the ones I thought were extraneous and in violation of NOT and EL. I didn't remove them all for the very reasons you give. I reluctantly left vischeck in because it has online versions available. I tried to find a better link to the online versions, but couldn't fine one that I thought would work well on its own. --Ronz 22:44, 19 February 2007 (UTC)

I somewhat agree with both Ronz and Fredhsu: The list of softare links is inappropriate for this article, however, they are not inappropriate for Wikipedia. Take a look at genealogy software and genealogy. Rather than make a link-list at the end of the genealogy article, the software products were turned into an article of their own right. I think the same should be done here. Create an article that discusses software solutions that have been developed to deal with or work around colorblindness. Include links in that article, and possibly create articles for some of the specific software products themselves if they are notable. I think an article on software solutions for colorblindness could have more potential than the geneology one, too, if it includes things such as discussions of the algorithms used and the techniques applied in the software. -- – Zawersh 12:24, 1 March 2007 (UTC)

I don't think genealogy software would stand up to an AfD from my experience. Still, I think it's worth pursuing the suggestion to create a new article on software solutions. --Ronz 16:11, 1 March 2007 (UTC)

I'm an absolute beginner as editor and I didn't notice the existence of the discussion page and the external link topic in it, so I just readded a link to the Accessibility color wheel. In my opinion it is still a valid link but if anyone wants to remove it again for the above mentioned reasons, it's ok --Gmazzocato 12:11, 30 October 2007 (UTC)

Thanks for taking the time to comment here. I've removed it. If you haven't already noticed, you have your own discussion page User talk:Gmazzocato where I had previously given you information about Wikipedia and editing. --Ronz 16:08, 30 October 2007 (UTC)

Proposal: Type and Color from Joe Clark's accessibility book.--K. 11:24 12 Mar 2008 (CET) —Preceding comment was added at 10:25, 12 March 2008 (UTC)

Monochromacy

In one section, certain symptoms (e.g. nystagmus) are associated with rod monochromacy, and in another they're associated with cone monochromacy. I haven't a clue which is correct, but someone should fix this. /blahedo (t) 14:59, 12 March 2007 (UTC)

Disability

I think more should be disussed on the nature of the disability. Why not as apparent as other issues Color blindness can preclude an individual from many careers. I myself realized this when I joined the military and despite the plethora of jobs, i was availed just two. Color blindness can effect education aswell.--66.30.196.201 05:29, 28 March 2007 (UTC)

Rainbow Errors?

On the tritanopia vision rainbow flag, there is blue, but that is the disorder with the absence of blue photoreceptors right? Can someone help me out on this? —The preceding unsigned comment was added by Kyle112 (talk • contribs) 13:24, March 30, 2007 (UTC).

Also in the RGB article there is a neat picture series with a barn, I'd like to see something like that viewed through the eyes of different color blindnesses. —The preceding unsigned comment was added by 75.30.219.118 (talk • contribs) 20:35, April 3, 2007 (UTC).}

DakeDesu: The rainbows are inaccurate. I suffer from a Red Green colour deficiency, and _all_the rainbows look completely different--on top of that I can distringuish the colours in them. Mind you, I don't match the colours the same as you say the colours are, but they are _extremely_ inaccurate views on colour deficiency.

If it is any importance, I am running version 7 of X.org, running Firefox on KDE() and GLX on Savage Card (CRT Monitor)

I believe the simulated rainbows are were calibrated so a normal-vision person will see how the a person with that deficiency would see it - so someone deficient in those colors looking at the simulated rainbow would be seeing it twice as off, so to speak. So they still wouldn't look exact. 128.118.31.28 (talk) 15:03, 9 November 2009 (UTC)

I agree; those of us that are affected shouldn't be able to tell the difference between the control and the rainbow that reflects our condition. Being color-blind I can't tell you WHY it's not right...I just know that it isn't!doctorwolfie 19:20, 4 September 2007 (UTC)

Not sure why, but the original LGBT flag isn't showing up right now... Not sure how to fix it... soldierx40k (talk) 22:17, 26 November 2007 (UTC)

I think this needs to get looked at, if it hasn't. When I originally saw the article I wondered how the image creator would have been able to do it, anyway, since assuming from the "control" (normal-vision rainbow), they didn't suffer from color blindness, yet were able to depict what a color blind person would see in the other rainbows. Wouldn't you just have to have people looking at the two rainbows until they said, "Yep, that matches." --Which, apparently, it doesn't, from these comments. —Preceding unsigned comment added by 98.222.76.79 (talk) 05:17, 10 December 2008 (UTC)

This has been here since 2007 and nobody has ever said they are correct have they, under anyones eyes and anyones monitors Deuteronomy is always wrong right? —Preceding unsigned comment added by 72.129.131.132 (talk) 18:36, 7 November 2009 (UTC)

Treatment?

There was a treatment for red/green colour blindness introduced a few years ago using a single coloured contact lens - should this be described; not by me I know nothing about it! Apepper 22:55, 30 March 2007 (UTC)

This is mentioned briefly under Color blindness#Treatment and management, but could certainly be expanded. The specific treatment you describe has been around for at least ten years -- I tried it for a few days back sometime in the mid to late 90's. One of the contacts had a red dot on it. I only have minimal anecdotal knowledge of it, which doesn't really qualify me to write about it either. :) – Zawersh 00:47, 12 April 2007 (UTC)

I had one of those in medical school; you can do the same thing with any lens (or piece of glass, plastic, etc) that is the color that you have trouble with. For example, a person with red-green color confusion can look at an object using a red lens. If the object is red, then it will appear "bright" through the red lens. If the object is green it will appear "dark" through the lens. It doesn't really correct the vision; it just gives you a trick so that you can figure out what color something is. It doesn't work with muted tones, because the white that is added into the color (to mute it) causes either color to "light up" when viewed through the lens. It helped with H&E stains though.doctorwolfie 19:27, 4 September 2007 (UTC)

Dyschromatopsia

"Dyschromatopsia is a symptom associated with the eye. Strictly refers to a disorder/change in colour vision." This was requested to become an article, however I believe it would be more suited if that sentence above was placed somewhere within this article. I wanted to place it somewhere, but I felt I leave it to someone with better judgement as this is a "Good Article". Then I will make a redirect for Dyschromatopsia into this article. Sounds good?(SORRY forgot to sign) petze 12:23, 1 April 2007 (UTC) Oh and PS, here is a refference for it: http://medical-dictionary.thefreedictionary.com/dyschromatopsia petze 12:27, 1 April 2007 (UTC)

ACTUALLY Dyschromatopsia is A AKA FOR color blindness. Omg how stupid of me..... I will add Dyscromatopsia as a AKA to color blindness and add the disease db on the info box and of course if anyone objects please discuss it with me. I shall also place a redirect for dyshromatopsia into color blidness. OMG i keep forgetting to sign...sorry petze 15:45, 13 April 2007 (UTC)

Dang...

Wouldn't that suck to have that. But wouldn't you not know if you have that condition if you were born with it since you would never know that you're vision is wrong?--Eloc Jcg 20:19, 14 April 2007 (UTC)

You'd figure it out over time when the rest of the world gives two or three different names to the exact same color, insisting, "That's not the green one, you idiot, that's red! That's the green one!" pointing to one that looks identical. --205.201.141.146 20:28, 27 June 2007 (UTC)

Benefit to Dichromacy?

Dichromacy and other forms of 'colour blindness' are much more prevalent among humans than other primates. It is likely that we are under much reduced evolutionary pressure, what with our food-sharing practices, which are rare in other animals, and this may explain it. However dichromacy occurs in other primate lineages as a norm (trichromacy is derived, and not as frequently as we would expect); it has been suggested that there may be benefits to dichromacy, such as the ability to 'see through' red-green camouflage.

Are there really such benefits to those who are red-gree colour blind (or other differences in vision)?

I think it may be worth mentioning in the article also that many organisms have up to 12 different colour photoreceptors (some shrimp... I don't have a ref to hand. Sorry); birds have 4 etc. It's important to realise that the number and response spectra of colour receptors are simply different ways of coding the reflectance spectrum of objects in the visual field; colour blindness is not 'wrong' or 'deficient' vision any more than 'normal' human colour vision. Trichromats are just as much lagging behind the colour vision of other animals, who have a very different and extended rainbow.

Also, should there be a link somewhere to Colour Constancy? —The preceding unsigned comment was added by 131.111.8.97 (talk • contribs) 10:28, April 20, 2007 (UTC). color blindness is alsowhen someone sees something in red and you see it in all different colors. There is many types of color blindness there is red color blindness there is shade color blindness there is black and white color blindness there is also color colorblindness. welllHie I am not here i love Gerard Way.

Old pictures

What happened to the old pictures (last time I chicked war 6 months ago) that had the numbers and a gray background and those who were a certain type of colorblindness couldn't read them? They are much better than the ones we have now, I would know as I am colorblid (as I'm sure many of you are too and also have an opinion, whether it be contrasting to mine), and those who wish to test themselves for colorblindness would find this fun and would get more viewers to the website. --24.225.156.40 00:24, 25 April 2007 (UTC)

There's some discussion regarding this above in the section Regarding the Sample Images. – Zawersh 12:55, 25 April 2007 (UTC)

Colorblind image template?

I'm red-green colorblind, and have on numerous occasions found images on Wikipedia whose colors were hard to fully distinguish (like this one). Have other people encountered this problem? If so, would a template for such images be appropriate?

--69.118.136.65 19:54, 9 June 2007 (UTC)

Such a template exists on Commons since yesterday: Commons:Template:Color blind. I hope people find it and start using it. Samulili (talk) 06:19, 15 May 2008 (UTC)

Doesn't add up

If 10% of men have some sort of color blindness, how can only 1.3% of the US population be color blind? I find it hard to believe that American are that much less likely to be color blind than the rest of the world. If the 10% number is correct than it should be closer to 5% of the American population. Hichris 17:18, 24 August 2007 (UTC)

This should be featured.

Just came to read up on this article,, and I see no real problems in it. It gives pretty much a flawless description of the whole thing, has attractive images, and while it doesn't have a whole truckload of references, it has enough reliable ones to justify FAness, I think. How d'you ask for something to become featured? AR Argon 05:14, 26 August 2007 (UTC)

Given a closer look at the article, it needs a quite a few more references, though everything else is practically flawless. Am I the only guy who wants to work at this article? AR Argon 22:28, 31 August 2007 (UTC)

There's a neat text "Color Vision; from Genes To Perception; edited by Karl R. Gegenfurtner and Lindsay T. Sharpe" which is a wealth of reference material. There was also an excellent article in Science ("The Chemistry of John Dalton's Color Blindness; Science Feb 17, 1995; 267;984-988)...how many references would you recommend?doctorwolfie 19:33, 4 September 2007 (UTC)

Question from reader's point of view

I cannot read the number 49 in Image:Colorblind4.png, but I can see:

• the Roy G. Biv in Image:Gay flag.svg,
• the 37 in Image:Colorblind3.png,
• the 56 in Image:Colorblind5.png,
• the 74 in Image:Ishihara 9.png,
• the red in apples....

Does that mean I'm colorblind in some form? Because, if I can see the other images and not just Image:Colorblind4.png, that leaves me very confused...I've even tried setting the brightness to very high and very low....I all I know is that I'm particually sensitive to bright light and bright colors, but not to an extreme.....THROUGH FIRE JUSTICE IS SERVED! 15:55, 16 September 2007 (UTC)

In fairness, the "49" is extremely subtle. This is just as easily caused by an uncalibrated or low-quality display (including an LCD set to a non-native resolution or anything below 24-bit color). In effect, a display can itself be "color blind" by having an insufficiently wide or dense gamut. Standardized tests in print are more reliable.

If you still can't see anything regardless of display settings, you may be mildly deuteranomalous. This is probably nothing that you'd notice in real life; only a standardized test might show that you are slightly worse at distinguishing unsaturated greens and reds than the average observer. 82.95.254.249 01:20, 21 October 2007 (UTC)

Regarding the apples

Regarding the apple simulation, I find one of the most confusing part of being colorblind, the so called simulations.

I have a deuteranomaly (I think). Yet I see a clearly red apple at upper left of the simulation. The apple looks (in terms of color) nothing like the apple on the right. The text states that the simulation applies to trichromat, which I gather I am. No quite into the technical terms.

Is the simulation wrong, or am I getting it wrong? Cypres 21:11, 16 September 2007 (UTC)

One of the possibilities is that the simulation gives you a double douse of color deficiancy. For example, If see greens that are half as bright, then an accurate simulation would appear only to have 25% green to someone with that type of color blindness

24.237.218.205 (talk) 02:59, 16 February 2008 (UTC)

Regarding camouflage spotters

The article reads: "Anomalous Trichromats are often able to readily spot camouflage clothing, netting, and paint that has been designed for individuals with color-normal vision. For the same reasons a color-blind painter might use too much blue to paint a green foliage landscape, a similarly color-blind artillery spotter would perceive too little blue dye used in camouflage created to match the same landscape."

Wouldn't this same artillery spotter see the landscape as having less blue dye, too? It seems entirely logical that if he perceives the clothing as having less blue dye than a color-normal person would, he would also perceive the landscape to be that way, giving him no advantage. I was under the impression that the advantage a color-anomalous person would have would be that the color-anomalous person would be better at picking up on texture and shape cues and not be as used to relying on color, thus not allowing his visual system to be fooled as easily. —Preceding unsigned comment added by 165.123.166.155 (talk) 14:52, 30 October 2007 (UTC)

I think the reason that colorblind marksmen have the advantage is that we rely more on processing shapes, rather than color. As in any disability one compensates for the skill that one doesn't have.doctorwolfie (talk) 11:44, 29 January 2008 (UTC)

What you say is true, but yes, for some reason it does also seem to actually affect color perception of camouflage itself sometimes. Check out this blog post: http://signaleer.blogspot.com/2006/02/color-blindness-benefits.html. US camouflage appears orange to him. I can back this up as a colorblind person, but not this incident specifically. There's a particular bush I see as grey. If I needed to find that bush out of a lot of bushes, it would be easy.... sometimes strange color "errors" occur which could be useful. DanOrc451 (talk) 17:53, 13 March 2009 (UTC)

My understanding is that people distinguish forms mainly on the basis of brightness contrasts rather than hue contrasts. People who lack a certain type of cone cell can see brightness differently because they are missing the contribution that that type of cell makes. Looie496 (talk) 21:15, 13 March 2009 (UTC)

"Causes" Section

In the "Causes" section, the first sentecnce of the second paragraph is:

The different kinds of worlds will end and the human color blindness result from problems with either the middle or long wavelength sensitive cone systems, and involve difficulties in discriminating reds, yellows, and greens from one another.

That sentence makes very little sense, especially the first part -- "The different kinds of worlds will end" This looks like vandalism? Or something weird going on! Can someone who is knowledgeable about this topic fix the sentence? Watercat04 (talk) 20:03, 15 December 2007 (UTC)

I have an issue with the causes section also. The beginning line in the third paragraph states, "When color blindness is inherited (which is almost always the case), it is inherited from the X chromosome." seems to be misleading. To my understanding, this is the case with common red-green color blindness, but it is not always the case for colorblindness in general. Blue-yellow colorblindness does not follow this rule. Although I am not sure if [4]is a reputable source, I believe it to be correct. It states, "Blue-yellow color blindness can be observed only very rarely. Different studies diverge a lot in the numbers but as a rule of thumb you could say one out of 10′000 persons is affected at most. In contrary to red-green color blindness tritan defects are autosomal and encoded on chromosome 7. This means tritanopia and tritanomaly are not sex-linked traits and therefore women and men are equally affected." This contradicts the statement from the causes section. If someone could revise the statement in that section to clarify how color blindness can be inherited, that would be great. 72.55.216.82 (talk) 00:17, 23 March 2008 (UTC)

The "causes" section really has nothing to do with the causes of colorblindness. I went to this article to find out, specifically, what are the physiological causes of colorblindness, and expected the Causes section to answer that question. The current first paragraph of the causes section is all about the benefits of recessive traits (in an undocumented way)... but, how does this explain the causes of colorblindness? The Causes section should have something like "one type, called blah-blah, is caused by .... Another type, called wuzzle-fuzzle, is caused by...." etc. This section really needs cleanup. In fact, since the actual descriptions of the causes are clearly laid out further down in the article, and this section doesn't really describe the causes of colorblindness, perhaps it should be eliminated entirely.

Neutral colours given as nanometre figures only... not good.

Is there some easy way of getting hold of a good basic guide as to what actual colours these numbers represent? I've played with spectrophotometers before and I'm still not super hot on how red/green/blue a particular number is, the average layperson reading this will be stumped and the containing statements will convey little useful information. If a person with a certain colour blindness cannot distinguish a pure light of 498nm from white light, what does this actually mean? What colour does that represent, and does it effectively mean they are seeing white "as" that colour? (Same as my seeing the pale orangey-yellow of my cheap 9w energy saving bulb as "white" on the various pieces of paper in the room where I am sat thanks to habituation and expectation, but if I concentrate on them, and compare them to the near-neutral white of the laptop backlight, it's easy to see the error). 82.46.180.56 (talk) 00:44, 17 April 2008 (UTC)

That's pretty much green; I labeled it. Dicklyon (talk) 01:23, 17 April 2008 (UTC)

Apple pictures

I looked long and hard at the apple pictures near the bottom of the page. I'm fairly certain the 2 "different" pictures are exactly the same, they just have the color channels changed (the core star and glare are the 2 most obvious identifiers. Even if great care was taken to set up different apples the exact same way, they wouldn't cut exactly the same or reflect exactly the same).74.167.173.21 (talk) 02:34, 6 May 2008 (UTC)

Well, it does says it's a simulation. It would be nice to know exactly what was done. Dicklyon (talk) 03:35, 6 May 2008 (UTC)

Yes, they're the same picture. The colors given by your monitor are a simulation of what a camera sees, what your camera sees is a simulation of what you see, so I don't see anything wrong with interpreting the color data to simulate what a colorblind person sees. It looks pretty much like the deuteranope simulation created by the Vischeck program: [5]. For protanopes the red (left) apple is much darker than the green (right) apple. You should probably mention this in the article; protanopes will see the image and say "that's not what I see". -- Madeleine ✉ ✍ 00:49, 23 May 2008 (UTC)

Ishihara tests biased?

I'm a deuteranomalous trichromat. I never knew something was different with my color vision until I was tested in school. If it were not for those tests, I would probably have gone through life without ever knowing. Suddenly I found myself barred from a number of occupations, and since then I've considered myself slightly disabled when it comes to vision. But after reading this article, I can't help wondering...

The question that has been nagging me is this: Do we, for a fact, know that it is not possible to construct an Ishihara like test that a deuteranomalous person can see, but not one with "normal" color vision? Has anyone ever tried? In other words, is the color vision of a deuteranomalous person really inferior to that of a person with normal color vision, or is it merely different? Is it possible that the Ishihara tests are biased for normal color vision?

After all, it wouldn't be the first time in history that those who differ from the majority is considered "defective" without any real basis for it. If you test motoric skills by putting a right-handed tool into the hands of a left-handed person, that person will indeed appear to be less skilled than others. And until recently, left-handedness was considered a disability. --Maggu (talk) 18:04, 21 June 2008 (UTC)

And, after a little searching, I found an article that seems to support that it would indeed be possible to construct such a test:

http://www.nature.com/news/2005/051205/full/news051205-1.html

--Maggu (talk) 19:39, 21 June 2008 (UTC)

Accessibility

There's a discussion at Template_talk:Tmbox#Accessibility that might interest some editors of this page. In particular, it would be nice to know whether the proposed talk page templates (similar to what's at the top of this page) are sufficiently readable for people with colorblindness, or whether a different/lighter background color is important. Your comments are particularly wanted. (If this issue in general interests you, then you might want to get in touch with WP:WikiProject Accessibility, too.)

Additionally, an editor has very kindly offered to figure out how to create a customizable "skin" to change the background colors in the templates if this would, in fact, be helpful to anyone. WhatamIdoing (talk) 15:58, 22 June 2008 (UTC)

Expand management?

Should we expand the "management" section to include some of the implications for daily life? I'm thinking primarily of limitations on occupations -- e.g., you can't work in most law enforcement positions if your "red car" or "tan shirt" isn't the same as everyone else's "red car" or "tan shirt" -- but it might be interesting to include limitations in daily life. I see that map reading is mentioned, but I saw nothing about dealing with one's own wardrobe, which can be a significant concern for some people. What do you think? WhatamIdoing (talk) 16:09, 22 June 2008 (UTC)

Hiding answers to tests

I've used Template:HiddenMultiLine to hide the answers to the tests. BTW congratulations on finding a test that really exposes my very mild deuteranopia - I have no problem with traffic lights, but in some parts of the Isihara test I see both numbers. -- Philcha (talk) 12:45, 1 August 2008 (UTC)

Birding

Hi . I am colour blind and am a keen birder. difficult eh? any tips.? Any way I can overcome the obvious problem of the red/ green / brown bird on a brown branch, surrounded by green leaves which to me is just a browny green job, if I see it at all, that is. Thanks. 190.152.46.23 (talk) 15:33, 1 September 2008 (UTC) John Norris.

I'm sorry, this isn't a general discussion forum. This page is for discussing improvements to this article. WhatamIdoing (talk) 21:43, 1 September 2008 (UTC)

Tritanopia

Does the picture for the tritanopia test actually have a number in it? The first one is clearly 37, the second is possibly 44 or 99, but the third picture doesn't appear to contain a number at all. Yet I'm sure I'm not colour blind. VonBlade (talk) 16:48, 19 September 2008 (UTC)

Maybe its because of your lcd monitor. I also didn't see the number at the beginning but after looking carefully it jumped out. It's a light pink colour, not very easy to see. Alejandro 189.7.84.37 (talk) 17:21, 19 September 2008 (UTC)

Colour deficiency?

I don't like the introduction to this article where colour blindness is expressed as a deficiency.

I am colour blind but I believe everyone has some level of colour blindness. For example take two colours #00FFFF and #00FFFE (see Hex_triplet#Hex_triplet). If you were to put these two colours next to each other say in Microsoft Paint the normal person would not be able to tell the difference between them. The computer can tell the difference as if they were black and white. It may take three or four separations of colour before the normal person can see the difference and may take more for colour blind people to see the difference. Therefore compared with a computer, everyone is colour blind to some extent. Darrenaustralia (talk) 07:45, 14 October 2008 (UTC)

A better example is some insects, which can see a much wider range of colors than any human can. But really the answer is that color blindness is defined as a deficiency with respect to the human norm, not with respect to some abstract ideal. If I can interpret your point as being that what I just said ought to be explained in the lead of this article, then I might agree with you -- the lead is a bit too short in any case. Looie496 (talk) 16:29, 14 October 2008 (UTC)

So the average person's ability to distinguish colors is less than ("deficient" compared to) a computer, and a colorblind person's is less than ("deficient" compared to) the average person's. What is the actual problem here? WhatamIdoing (talk) 16:39, 14 October 2008 (UTC)

See the definitions of deficient: could it be that a colorblind person might take offense at being called inadequate, insufficient, falling short of some prescribed norm, lacking something essential, incomplete, or defective? Dicklyon (talk) 18:16, 14 October 2008 (UTC)

Citation needed? Really?

">It should also be noted that even though some people are unable to see some or maybe even any of the numbers in (e.g., red-green) color blindness tests, they might still be able to tell the difference between the colors in their everyday lives.[citation needed]" Where can you cite something like that? As for me: when I was about 7th or 8th grade (God, time flies!) we talked in Biology about eyes. Our teacher showed us some tests and, accroding to the result, 4 of us, including me, were red-green-blind (with only one being clinically diagnosed!) She explained to us that there are very mild cases that don't interfere with every day life, so some people (including the three of us) can normally distinguish between red and green, but can't when it looks to similiar. I also know others who say the same. Now I read this article and wondered why a citation is needed. I know it's true, the author apperantly knows it's true, but how can you CITE it's true? <-- unsigned, was added by 91.62.53.55 at 15:01, 30 November 2008

There are generally two reasons why people add "citation needed" tags: either they are being pedantic, or else they are skeptical of the claim and want to see some published support for it. Unfortunately, personal knowledge doesn't really solve the problem: there are lots of things that people "know" that aren't actually true. (I'm not saying that this is one of them.) Looie496 (talk) 18:07, 30 November 2008 (UTC)

This also brings up the great juxtaposition where if you're told a certain colour is red then that's what you call it. It doesn't matter what colour you see, because we can't tell that. So if you see red as blue, and people tell you it's red, then you associate blue with red and nobody would be any the wiser. Hmm. I'm not sure juxtaposition is the word I want. VonBlade (talk) 21:41, 15 January 2009 (UTC)

Coming back to 91.62.53.55's question, I agree that some people have sub-par red-green discrimination according to the tests, but have no problems with traffic lights - I'm one of them (apart from speeding up when I see the orange). However one of Wikipedia's basic principles is no original reasearch, which is semi-polite jargon for "you can't just state your own personal opinions in articles" - you can imagine what would happen if that was allowed. In addition finding a reliable source for this point might provide other useful and interesting information, e.g. what % are "normal", what % get around OK but are bad at colour-matching their clothes, what % should not be allowed to drive, etc. --Philcha (talk) 22:48, 15 January 2009 (UTC)

Statistics

Are there any statistics that show the percentage of people with multiple trichromacies? For example, I have Protanomaly and Deuteranomaly and am curious as to how common that is. Are the various color blindnesses randomly overlapping, or are persons with one type of color blindness more likely to have others also? 24.237.218.205 (talk) 05:21, 8 December 2007 (UTC)

http://www.bbc.co.uk/health/mens_health/issues_colour.shtml This gives total colour blindness for men as 5% and women 0.5% I want to add that but cannot find reference list #2 to add the URL Rangutan —Preceding unsigned comment added by Rangutan (talk • contribs) 07:24, 20 December 2009 (UTC)

We need to put this on the page somewhere.

http://upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Achromatopsia_failure_modes.jpg/600px-Achromatopsia_failure_modes.jpg —Preceding unsigned comment added by DJLO (talk • contribs) 01:50, 21 December 2008 (UTC)

"White deficiency"

I tagged the section as disputed. It seems to be a neologism at best. Sources? --Ronz (talk) 21:09, 15 January 2009 (UTC)

LOOK OUT FOR VANDALS!

I found this under "types":

There are many types of color blindness. The most common are red-green hereditary this most commonly leads to doom or death!!!! Now that you have read this you have 24 hours to live! ;0

I will get rid of the vadalized part, but we need to watch out for vandals (and no, you will NOT die in 24 hours.)--Sonicobbsessed (talk) 00:55, 24 February 2009 (UTC)

UPDATE Whenever i click "edit this page" the vadilizim part, "There are many types of color blindness. The most common are red-green hereditary this most commonly leads to doom or death!!!! Now that you have read this you have 24 hours to live! ;0" does not show up, but it is still in the article, I CANT GET RID OF IT! D:< --Sonicobbsessed (talk) 00:58, 24 February 2009 (UTC)

For some reason the page wasn't updated after the edit that removed that material. I fixed it by doing a "null edit" of the full article. You might take a look at Wikipedia:Purge to learn more about why this sort of thing sometimes happens. Anyway, thanks for pointing it out. Looie496 (talk) 04:30, 24 February 2009 (UTC)

Notable color blind people

many famous people are color blind. We should have a category for this--76.116.105.50 (talk) 04:16, 1 March 2009 (UTC)

% occurrence of Tritanomaly

i just thought that i should point this out- that where it should say the percent occurrence of Tritanomaly it just says that it is the same chance in males and females. on second thought the source article probably didn't say the percentages and said that instead. 216.246.227.26 (talk) 21:41, 26 March 2009 (UTC)

found the info in the chart in the section "Prevalence" going to fix itWalkerm930 (talk) 00:01, 27 March 2009 (UTC)

GA Reassessment

This discussion is transcluded from Talk:Color blindness/GA1. The edit link for this section can be used to add comments to the reassessment.

GA Sweeps: Delisted

As part of the WikiProject Good Articles, we're doing sweeps to go over all of the current GAs and see if they still meet the GA criteria. I believe the article currently has multiple issues that need to be addressed, and as a result, I have delisted the article. Although many inline citations are present, there are several sections that lack citations and there are many "citation needed" tags throughout the article (some back from December 2007) as well as other cleanup tags. In addition, the lead needs to be expanded (see WP:LEAD for guidelines). Add additional sources from a variety of sources to provide a balanced representation of the information present. Perhaps sources can be pulled from the main articles linked to within the article. Look to books, magazines, newspaper articles, other websites, etc. Although it has been delisted, the article can be return to GA status by addressing the above points. Once sources are added and cleanup is done, I recommend renominating the article at WP:GAN. If you need assistance with any of these issues, please contact me on my talk page and I'll do my best to help you out. --Happy editing! Nehrams2020 (talk • contrib) 06:31, 18 May 2009 (UTC)

Cure?

"In a study published on September 16 by the journal Nature, scientists say they have used gene therapy to cure red-green color blindness in two adult male squirrel monkeys."

Full article at: Steven J. DuBord (2009-09-18). "Gene Therapy Cures Color-blind Monkeys". The New American magazine. Retrieved 2009-09-21. — Loadmaster (talk) 20:17, 21 September 2009 (UTC)

Hideous ambiguity

there is insufficient apparent difference between the red and amber and sodium street lamps and the green can be confused with a grubby white lamp

Needs a comma to be unambiguously parsable. I think I know where it should go, but can't be sure. 72.75.67.226 (talk) 09:17, 19 October 2009 (UTC)

I've had a try at it. May need to be split into two separate sentences. Andrew Oakley (talk) 16:35, 19 October 2009 (UTC)

Why "dubious - discuss"?

The section Causes, alleges:

Any recessive genetic characteristic that persists at a level as high as 5% is generally regarded as possibly having some advantage over the long term.^{[dubious – discuss]}

Is this dubious, and then why? Next sentence ends by someone asking for a citation, and such a request is of course valid, but I thought it was common knowledge that unusually common genetical variations that may (with too many prejudicies) be perceived as "defects", usually come with some secondary advantage, f.ex. sickle cell anemia and possibly homosexuality. And humans are not free from a selective pressure, the culture provides us with myriads of survival requirements to be "successful". ... said: Rursus (^mbork³) 18:33, 27 October 2009 (UTC)

Just cite a source, and it won't be dubious any more. Dicklyon (talk) 19:34, 27 October 2009 (UTC)

Of course! But the inline template should then be [citation needed]. I'll substitute. Anyone who dislikes, may reinsert [dubious - discuss], but a section named Dubious should then be added and explained in this talk page. Rursus dixit. (^mbork³!) 10:41, 9 February 2010 (UTC)

CIE chromaticity diagram

Could someone simulate the CIE chromaticity diagram with different dichromacies (with monochromacy the diagram would be a single color)? Totsugeki (talk) 20:38, 1 December 2009 (UTC)

I'll answer to myself. With this website [6] you can simulate the chromaticity picture [7]. Totsugeki (talk) 20:40, 1 December 2009 (UTC)

Incorrect information

The is a section as follows: "Research published in 2009 carried out by the City University of London's Applied Vision Research Centre, sponsored by the UK's Civil Aviation Authority and the US Federal Aviation Administration, has established a more accurate assessment of colour deficiencies in pilot applicants' red-green and yellow-blue colour range which could lead to a 35% increase in the number of prospective pilots meeting the minimum medical threshold.[34]"

Going to the cited page and reading more than the tag sentence at the start, you'll see the 35% figure is used incorrectly. The use of the tests would reduce the number of people rejected by 35%, not increase the number accepted by 35%. Near the end of the article, it states that quite clearly.

Look at it this way: If 10,000 men apply to be certified, approximately 800 will get rejected due to color-blindness. The better test would let 35% of the 800 (that's 280) in. The way it is stated ("35% increase in the number of prospective pilots meeting the minimum") would increase the 9,200 currently accepted by 35% to 12,420, more than actually applied! Jursamaj (talk) 07:21, 17 December 2009 (UTC)

Well spotted - I've changed it. If you find anything else like that the best thing to do is to be bold and change yourself with an explanation in the edit summary. Richerman (talk) 13:51, 17 December 2009 (UTC)

Traffic lights

The article mentions that red/green colour blindness makes it difficult to distinguish traffic lights by colour; in the UK - and presumably throughout Europe the green light has added blue so it looks quite different from the red even if, like me, one is red/green colour blind. If anyone has a reference to confirm this (ISTR hearing it on the radio once) then shouldn't this be in the article?

Apepper 22:53, 30 March 2007 (UTC)

• I know for a fact that in the United States (at least) one of the lights (I forgot which, I'll do research) appears brighter to colorblind individuals. Kevingamer 01:08, 10 April 2007 (UTC)

Last I heard, the main cue in traffic lights that color blind people were supposed to follow is position - which light is on. --Ronz 01:13, 10 April 2007 (UTC)

That's probably true, but I can't distinguish red/green LEDs but I can easily tell the difference between red/green traffic lights. Apepper 16:46, 16 April 2007 (UTC)

The traffic light article has some mention of colors added: "Usually, the red light contains some orange in its hue, and the green light contains some blue, to provide some support for people with red-green color blindness." It is not cited, though. They also have a picture of a traffic light in Nova Scotia that uses special shapes to help color blind individuals. – Zawersh 00:39, 12 April 2007 (UTC)

Here in the Netherlands the green light tends to be a bluish green. No reference, sorry, maybe I'll look for that when I have more time. --Jonathanvt 19:18, 23 May 2007 (UTC)

As a colorblind individual in the US, I can confirm that 1. It's hard for me to distinguish the yellow light from the red light and 2.) the green light actually appears to be white. The only thing that saves me is I know its red, yellow, green. However, that doesnt help when it's a single blinking yellow or red light, I never know whether to stop (blinking red) or slow down (blinking yellow). Tjshome 20:05, 6 November 2007 (UTC)

Excuse me for this possibly stupid question but can't you tell which light is it by its position (i.e. the higher one means stop, the lower one means go?) 194.90.37.111 (talk) 19:33, 31 March 2008 (UTC)

Most of the time you can (this is how I look at traffic lights), but this can be hard in some situations, like fog, or with horizontal lights. At night it can also be very difficult to see enough of the traffic light assembly to know which position is on. My grandfather also told of one state (which escapes me now) where the lights were reversed. I'm sure this is no longer the case, though. 76.104.173.177 (talk) 21:51, 1 April 2008 (UTC)

I know this thread is 3 years old, but Japanese actually call the traffic light, "red, yellow and BLUE" not green, they consider green to be a shade of blue.--DCX (talk) 04:35, 28 March 2010 (UTC)

color vs colour

i feel the article should spell colour in english, not american —Preceding unsigned comment added by 96.237.131.107 (talk) 20:23, 3 May 2010 (UTC)

See WP:ENGVAR. This article is not relevant more to either Commonwealth or American readers, so it could have used either spelling. Since it started using American spelling, we continue to use that because to change it would only lead to spelling wars.-gadfium 02:11, 4 May 2010 (UTC)

Color blindness spectrum comparison

I used a color blindness simulator to generate a color spectrum in each common type of color blindness. The result is to the right. I made this because I wanted a convenient way to compare hues in different color blindness types at a glance. Maybe it would be useful to other people? Nanobot (talk) 06:04, 27 September 2009 (UTC)

I wonder what the copyright on this is? Doc James (talk · contribs · email) 19:56, 17 May 2010 (UTC)

WP:MEDMOS

Have attempted to rearrange per the above. The causes section approaches the same thing from different directions thus resulting in duplication. Doc James (talk · contribs · email) 19:51, 17 May 2010 (UTC)

Need review by people who ARE colorblind

My girlfriend linked me to this page recently, and from many perspectives I'm very worried. From the many tests I've taken and what I know about the physiology, technical details are incorrect. Useful descriptions are entirely lacking. The rainbow pictures are totally absurd, since, according to those, I am not colorblind at all! Looking over discussion from some years ago, it's preposterous that we have non-colorblind people debating how colorblind people see. Of course, if I start editing things on that level, it may become too subjective, but this idea of "I heard it was this way" is a lot more hearsay and subjective than, "I'm colorblind and it looks this way." Personally, I would value scientific information on the site more than my own opinion (up to the point of contradicting experience, which so far this article succeeds at), and give basically no credit to casual editors who are also not colorblind. Sorry to be rude if it comes across that way. Even the color tests shown here aren't very good. But for an article that was once a feature article, this is not impressive besides its length to me. And yes, I do edit pages, and no, I'm not just passing through complaining. I won't have time to make changes anytime soon, and I'd need to do research before I was confident to make many changes. I'd like to know how other people think about my comments here! DAID (talk) 04:02, 18 May 2010 (UTC)

I've now read the whole article, and here are some specific problems. Firstly, the organization is poor, and many topics are repeated very often rather than condensed. We have a section By Causes and then under the former topic of Classification a subsection Causes; this section is fruitless particularly because the "Acquired" bullet point literally has no information or subtopics whatsoever. A point which connects organization to content is the point of "What do readers really want to know?" Of course I can't tell you that, but being colorblind, anyone I ever talked to who was engaged or interested in something I said was always more interested in either function or perspectives. The function aspects of the article are far underneath the technical details of the article, and the perspectives are limited to images which are probably not appropriate for display on computer screens; in a rare case for me so far on Wikipedia, an article contains information which might correct itself, yet it is not used! That is to say, the article spells out that different media may affect greatly how colorblind individuals see a color, and yet I have a strong feeling a number of the example images presented here were NOT intended for computer display, thus making most of them rather uninteresting even to me as a colorblind person, and probably grossly misleading to other readers of the article. As far as the Airforce goes, I am aware that the British air force was using colorblind people in WWII, and this article cites the US Air Force first for recognizing this advantage; is that really true? There is information which appears contradictory concerning what happens to female carriers. In one part the article suggests they may have tetracolor vision (with no interesting statement actually confirming this, it's merely hypothetical), and another part suggesting males are affected because they don't have an X chromosome to OVERRIDE the 'faulty' one. If the dominate X chromosome is overriding the recessive one, then necessarily females could not have tetracolor vision from this argument. That needs to be cleared up and made consistent throughout, or the idea of female tetracolor vision removed or put to some kind of footnote or speculation. There is no discussion about how cones respond to ALL frequencies of light, which is a fact (they just respond more strongly to certain frequencies). In this way, there is a very serious confusion in the article of cones with rods; there is the statement many times (too many for good organization) that individuals with only one functional cone are monochromatic. From a physics perspective this is nonsense. An item that is sensitive to light intensity and not wavelength and an item that is sensitive to both intensity and frequency at least gives one color data point. Thus, individuals with only one cone, by physics logic, cannot be as colorblind as individuals with no cones at all. Getting into physics, this article has none, which is inane. One might bother mentioning that color is purely an evolutionary convenience with nearly no physical meaning. Yes, there are different wavelengths of light, but the cutoffs for different colors are arbitrary and entirely meanlingless. The wavelengths the human eye are even sensitive to are extremely limited, and only arose from evolution because our sun peaks near the "yellow" part of the electromagnetic spectrum, and Earth's atmosphere is mostly transparent in this region. There is an idea about how the "mass" of a color may afflict the colorblind, but there is no mention that introductory psychology text books even give this as a general example universal to the properties of vision for all humans: small red dots look the same as small black dots. The notions of traffic lights discussed here is atrocious, stereotyped, and misses the points. All non-colorblind people I talked to have merely assumed that we colorblind distinguish based on position. Any colorblind person I ever talked to starkly disagreed. The traffic lights that are solid are fine. It's the flashing red and flashing yellow lights that are hard to tell apart from a distance. And one might also mention that green lights in Japan are also much more blue, and as far as I know, this has nothing to do with colorblindness. As far as general interest, one might really like to know why color vision even exists, particularly upon the revelation that it is physically arbitrary. It's a co-evolution of fruits with fruit-eating animals. If one compares carnivores to herbivores or omnivores, one can clearly see this trend. It's the exact same reason that fruits taste sweet and sweetness is appealing that many fruits are bright shiny colors that normal color vision perceives as attractive and standing out. Discussion of human female tetracolor vision aside, some primates have been proven to normally have tetracolor vision. Such a discussion of "what other color could these tetracolor primates see" leads readily to the discussion that "color is physically arbitrary" and may help to quash many prevalent stereotypes about color vision. I actually didn't say everything I wanted to, but well, my first comment wasn't so specific, which might feel unhelpful. So there are some specifics to chew on. If I'm mistaken at any point, of course, that's why this is on the discussion page. DAID (talk) 05:03, 18 May 2010 (UTC)

I didn't realize there were stereotypes about color vision. Not once in my life have I heard anyone joke about color blindness or make fun of anyone with any form of color blindness, nor have I heard any mention of it outside topical conversation. Verifiable sources for your discussion (as per Wiki rules) would be excellent and could justify making changes or additions to the article. Please leave self-ingratiating crusades at other forums.

As a software developer, the plausibility of color-blind users employing my software has a profound impact on how I design user-interfaces. I also have a color-blind friend who I turn to for pointers. If he has trouble distinguishing anything, I can make changes before the product is released. Obviously, his particular condition is merely the most common, but his feedback is useful; I use simulated colors for the rest. This article, among other sources, has proven very beneficial to me given my limited "normal" vision. —Preceding unsigned comment added by Thatfield977 (talk • contribs) 18:02, 27 May 2010 (UTC)

A few comments on what you've said:

I would agree that the article could do with some restructuring and removal of uncited information, however:

• Your assertion that there needs to be a review by people who are colourblind is incorrect - wikipedia is about verifiability not personal experience. Anyway, I have a red-green colour deficiency and I have read the article and made a number of contributions.

• The rainbow pictures illustrate the differences between the perception of colour by normal individuals and those with various colour deficiences. Obviously they are designed to show those with normal vision how others see the world and they don't really work for individuals with a colour deficiency, although they will give us an idea of the differences between the various degrees of colour deficiency.

• The article doesn't say that the US Air Force were the first to to use colour blind individuals, it just doesn't happen to mention the British Air Force, presumably because no-one has found a suitable reference. If you can find one go ahead and add it.

• "it's preposterous that we have non-colorblind people debating how colorblind people see". That's ridiculous! - perhaps you think we should abandon the study of neuroscience, psychiatry and psychology altogether as we can't know exactly how someone else thinks or perceives the world? It obviously quite easy to work out what someone can see if they are lacking the perception of of certain wavelengths of light - you just subtract those wavelengths from the final image.

• As for your point about traffic lights, I don't have any problem with them other than the red light is not as bright as the other two. However, I would expect that for people with a more pronounced deficiency the position of the light would be what they would use, which goes back to my first earlier point about verifiability, as our own perceptions aren't necessarily of much value. Richerman (talk) 01:09, 28 May 2010 (UTC)

Precise source needed

I have changed text:

"Test for Deuteranopia[Note 1] This image shows a number 49, but someone who is deuteranopic may not be able to see it.";

under picture to:

"Test for Deuteranopia[Note 1] This image shows a number 44, but someone who is deuteranopic may not be able to see it.",

because in a hard print of my source there is as answer stated number 44. Since my source is weekly magazine I am not sure which answer is correct so if anyone has a more reliable source to verify the answer please do. —Preceding unsigned comment added by Hrvatistan (talk • contribs) 00:26, 1 July 2010 (UTC)

I'm completely confused by what you're trying to do. The number in the test on the screen is what it is - how can you have a source for it? The picture in your magazine is obviously not the same one. If you click on the picture you will find in the original file it says "Someone who is deuteranopic might not see this number (49). Please note that the second digit in this number may be difficult to discern even by those with normal vision." If you can't see what it is then don't change it. Richerman (talk) 01:48, 1 July 2010 (UTC)

Recent medical breakthroughs?

I was recently reading about Color Blindness on this page: http://news.nationalgeographic.com/news/2009/09/090916-color-blind-gene-monkeys.html talking about gene research that has allowed red-green color blind monkeys to regain normal eyesight. I do not have the expertise to add this information to this wiki page, but I'm somewhat surprised that there is no mention of medical research towards this (nor on the discussion page). Just a heads up in case someone with more knowledge on the subject would like to elaborate or refute these claims. —Preceding unsigned comment added by 174.19.118.151 (talk) 14:35, 13 July 2010 (UTC)

Misconceptions and compensations

The section on Misconceptions seems contradictory. It states "Color blindness is not the swapping of colors by the observer — grass is never red, and stop signs are never green". And then to the right of this paragraph, we see a picture of how a person with dichromacy sees a red apple ... and it's green. (i don't have color blindness btw) —Preceding unsigned comment added by 128.148.60.31 (talk) 17:49, 26 August 2010 (UTC)

It seems contradictory at first, but there is no better way to demonstrate the condition to a trichromat. We can only simulate bichromacy by combining two colours into one. The viewer must imagine that red and green are the same colour. Maybe the explanation for this is lacking? 209.87.231.80 (talk) 20:34, 3 November 2010 (UTC)

Suitability of the head illustration

Regarding the illustration named US Flag color blind.png

The article explains that the condition is manifest to the person as ambiguity, not reversal of red and green. Despite this, the illustration indicates that a red-blind person perceives a green American flag! This illustration represents a common misconception, not the reality. Therefore it should not be used to headline the article. It would be better used in section: "Misconceptions and compensations". —Preceding unsigned comment added by 209.87.231.80 (talk) 20:29, 3 November 2010 (UTC)

"Invitation to edit" trial

It has been proposed at Wikipedia talk:Invitation to edit that, because of the relatively high number of IP editors attracted to Color blindness, it form part of a one month trial of a strategy aimed at improving the quality of new editors' contributions to health-related articles. It would involve placing this:

You can edit this page. Click here to find out how.

at the top of the article, linking to this mini-tutorial about MEDRS sourcing, citing and content, as well as basic procedures, and links to help pages. Your comments regarding the strategy are invited at the project talk page, and comments here, regarding the appropriateness of trialling it on this article, would be appreciated. Anthony (talk) 12:05, 31 August 2010 (UTC)

The list of articles for the trial is being reconsidered, in light of feedback from editors, and should be ready in a day or two. If you have any thoughts about the Invitation to edit proposal, they would be very welcome at the project talk page. Anthony (talk) 14:46, 2 September 2010 (UTC)

OMG!I love this class! —Preceding unsigned comment added by 198.108.245.98 (talk) 15:04, 23 November 2010 (UTC)

Something's not right here

In the "Misconceptions and compensations" section it said "Anomalous Trichromats tend to learn to use texture and shape clues and so are often able to spot camouflage clothing, netting, and paint that has been designed to deceive individuals with color-normal vision." cited with reference 1, which is about Dalton. I don't know what's going on but the Dalton reference is obviously not right. I've replaced the reference with ref 2 and changed "anomalous trichromats" to "dichromats" as that's what reference 2 says. There is, however, a reference to "anomalous trichromats" here if someone wants to plough through it. Richerman (talk) 02:09, 13 November 2010 (UTC)

Eye Color receptors

According to [Color] the three cones color peaks are:

S: 420nm in the violet sector (400-450nm),

M: 534nm in the green sector (490-560nm), and

L: 564nm in the yellow sector (560-590nm) bordering on green - greenish yellow, if you will.

Observation: This makes sense in seeing the closeness of red blindness (loss of the greenish yellow channel) and green blindness (loss of the green channel). Understanding that the definitions of these colors are hazy not sharp edged, is calling them blue, green and yellow appropriate? SkoreKeep (talk) 21:13, 18 February 2011 (UTC)

Could we get a better Tritanopia test picture?

I am confident that I have no form of color blindness, but it is almost impossible to see the "56" in the "tritanopia" color blind test that is on this page. I have showed this picture to several other people and they all agreed that it was nearly impossible to see even for people with no color-blindness, and I also stumbled upon a forum post that used this as a link, and the consensus seemed to be that it was too difficult for them to see as well. The image tag does state that "Image may not be visible on LCD or with excessive screen glare." Considering that many computer screens are LCD nowadays, that just seems rather impractical, and this picture could be misleading to some people. bob rulz (talk) 13:47, 20 March 2011 (UTC)

What image would you use to replace it? Looie496 (talk) 17:06, 20 March 2011 (UTC)

Citation 10

I noticed that there was a problem with citation 10 (used only in section: 3.1). I went to the website listed, and indeed the cited facts do not appear on that page. However, they do appear on a different page on the site: http://www.toledo-bend.com/colorblind/cbinfo.asp. I wouldn't know how to fix the citation thing, and I am unable to even try from where I am (a university). So if someone else could look at it that would be great. I also don't know if the source is actually good... but that's a whole other topic.129.82.226.96 (talk) 20:34, 28 March 2011 (UTC)

color

Hello. If color blind people view the image for color blind then ? A person who has been editing Wikipedia since October 28, 2010. (talk) 21:47, 14 July 2011 (UTC)

Swapping red for green?

I am confused by these sentences in the "Misconceptions" section: "Color blindness is not the swapping of colors by the observer — grass is never red, and stop signs are never green. The color impaired do not learn to call red "green" and vice versa." Surely if a person is unable to distinguish between red and green that is exactly what may happen? All of the example pictures in the rest of the article work by swapping colours, usually red and green for yellow (although I appreciate that it may be difficult or impossible to demonstrate colourblindness any other way). Am I misreading this quote (and should it therefore be rewritten to be more clear) or is there some important point I am missing (which should be clarified in or after the quoted section)? 121.45.176.80 (talk) 11:29, 5 August 2011 (UTC)

I think this should be removed as I am not sure that anyone thinks that red and green are swapped by the observer - there is certainly no citation to support the notion that anyone does. As to your point about that being possible I don't think it is - someone who couldn't distinguish between red and green may make a guess and choose the wrong answer but they wouldn't consistently call red "green" or vice versa. I'm protanomalous and the main misconception I find is that people think I can't discriminate between red or green, whereas it's just the intensity of the hue that's reduced. The main effects of this in the real world are that, to me, the red traffic light doesn't appear to be as bright as the green and amber lights, and in poor lighting I may confuse reds and browns. I also struggle find small edits others have made in wikipedia as they're highlighted in red - not a good choice of colour from my point of view!

In the same section I have a problem with the meaning of the sentence "This is a risk factor on high-speed undulating roads where angular cues can't be used". What "angular cues" are being referred to? Does it mean the relative positions of the traffic lights? Richerman (talk) 00:09, 6 August 2011 (UTC)

My confusion apparently stems from the use of the word "swap". I understand "swapping of colors" in the offending section to mean that a color blind person sees a color that is not red ("swapping" red for another color) where people with full color vision would see red (for example). The other interpretation, that a color blind person sees everything green as red and everything red as green is simply nonsensical: what would that even mean, and how would one go about verifying it? If this is the meaning of the offending section I agree that it should be removed, since nobody holds such a misconception and the very idea makes no sense. Furthurmore, the statement seems to apply more to some forms of color blindness than others. Deuteranopia, for example, is described in its own section of the article in such a way that sounds to me exactly like what the offending section claims is a misconception (i.e. that red, yellow, and green all look alike). Perhaps it should be replaced with reference to the misconception that all forms of color blindness are identical? However, that may be redundant as the rest of the article makes that fairly clear. 121.45.176.80 (talk) 05:56, 9 August 2011 (UTC)

As that's the only misconception mentioned and it isn't verifiable I'm removing it from the title and deleting the sentence. Richerman (talk) 07:07, 9 August 2011 (UTC)

Color tests

I have never been diagnosed as being color blind, but I can barely make out only the first of the numbers in the first set of circles. I wonder if the reporuction is incorrect or if perhaps the settings on the computer I am currently using are at fault?211.225.34.66 (talk) 05:46, 21 September 2011 (UTC)

Can you copy the image to this section, so we can be sure we all talk about the same image? Eddau (talk) 13:56, 21 September 2011 (UTC)

Start with a zero-cost method: Find a female friend or family member (because there is enormously less chance that she might be colour blind) who you can trust not to deceive you, even for fun. Go with her to a known good computer (is there one in your local library?) and under her supervision do the Ishihara test. Google will find plenty of those online. Take it from there. Old_Wombat (talk) 11:11, 26 September 2011 (UTC)

Resources for designers

I found this resource useful and interesting, but I can't at this moment figure a way to gracefully integrate it into the article. (71.233.167.118 (talk) 02:02, 20 October 2011 (UTC))

Animals

I came here looking for a survey of what colours animals can see; it turned out to be elsewhere on the wiki, so I linked it. But it occurs to me there's a related topic that should be covered here: species-relative color-blindness in animals. For instance, do we ever find individual dogs that can only see black and white? If any editors have some knowledge of this subject, it would make a good addition to the article. ~ CZeke (talk) 16:16, 9 November 2011 (UTC)

Vote to Remove "Evolutionary arguments"

or at the least change the heading title. This section points out possible advantages that color blindness may afford those afflicted with the condition, but makes no attempt to associate those advantages with possible evolutionary influence. I assume that the author is trying to point out possible associations colorblindness may have on "survival of the fittest" in certain circumstances, but I would suggest that the circumstances described are so limited as to be inconsequential to the evolution of our species. It is also possible that the author is attempting to "prove" that evolution as an inter-species phenomenon exists by his comparison of colorblindness between humans and monkeys. If that is the case, the argument is far too weak. It wreaks of personal bias and opinion, and has no business being included in an encyclopedic article. I will leave it as is for the time being and let others chime in with their opinion. A2Z (talk) 16:11, 12 November 2011 (UTC)

Rename, "Evolutionary Considerations?"

I agree that this section be removed, otherwise it needs to be substantially improved and change the title. There is a body of literature on evolution and color vision. See for example, citation #3. However, even this reference concludes that the reason for the high prevalence of color blindness is still speculative.

There is a statement about possible evolutionary advantages in the introduction of this article, so this idea probably there is little need to bring the topic up again as an entire section, with so little to bolster it. Regarding the army anecdote, I remember seeing an old WWII movie that depicted a U.S. soldier who was color blind and therefore could see enemy camouflage, so I wonder if the story is something invented by Hollywood. mattelfesso (talk) 18:01, 2 April 2012 (UTC)

The missing reference?

http://www.colblindor.com/2010/06/02/color-blind-observers-for-national-defense/ — Preceding unsigned comment added by 77.193.134.70 (talk) 23:23, 12 May 2012 (UTC)

"Able-bodied"?!?

The caption on the | Ishihara comparison refers to non-colorblind people as "Able-bodied." I hardly think this is a correct label, and the fact you see the plate properly does not necessarily mean your body is able of anything other than color vision. Speaking as a deuteranope, other than having a hard time telling my purple climbing rope from the blue one, and the occasional ill-advised selection of a neck tie, I have not run into major problems doing fairly advanced mountaineering/rock climbing/ice climbing, mtn bike racing, back country skiing, or practicing medicine.

Perhaps this should be changed to "normal vision". — Preceding unsigned comment added by 69.140.37.77 (talk) 21:51, 31 May 2012 (UTC)

That caption doesn't appear in this article; only the associated image does. It's a Commons image, and you can open a discussion about it by clicking here or simply change the file page yourself (using an edit summary to provide your rationale, of course). A complicating factor is that the phrase "able-bodied" appears not only in the caption but in the actual image, so you'd have to edit the jpeg itself to change the wording. Having a friendly word with the editor who uploaded it might be the best way forward. Rivertorch (talk) 22:39, 31 May 2012 (UTC)

Rainbow *anopia.svg

           
I recently fixed numerous errors in "Rainbow_Deuteranopia". But "Rainbow_Protanopia" is erroneous too (at least, red is too bright); unsure whether there are such mistakes in "Rainbow_Tritanopia". Rush to fix all mistakes before Commons forbade fixes in any image. Incnis Mrsi (talk) 13:39, 31 August 2012 (UTC)

Of, course, there was an error in previous versions of "Rainbow_Tritanopia": the violet/purple stripe was impossibly bright. I fixed this and uploaded the new image where R_tri = R, G_tri = B_tri = (7·G + B) ∕ 8, by the way turning the hue contrast to red–cyan from something like pink–azure in previous versions. This is a matter of taste because tritanopes do not distinguish red from pink and cyan from azure, but is seems easier to me to make calculations in red–cyan. Why not simply G_tri = B_tri = G, indeed? Because G ≠ Y and B ≠ Z, the Y (and hence G_tri) depends not only on G, but slightly on B too. Although I implemented a quite dirty formula, it reflects the idea that RGB’s "blue" is not really black for a tritanope and should be taken with some weight, although a small one. Incnis Mrsi (talk) 16:24, 31 August 2012 (UTC)

Looking to this colour map, understand that R_tri = R, G_tri = (7·G + B) ∕ 8 was not a good idea and I have to remade the job. Any suggestions? Incnis Mrsi (talk) 16:40, 31 August 2012 (UTC)

I don't know this material, but it seems oversimplified. If the perception is as simple as the saturated rainbow charts suggest, then why does Ishihara use nonsaturated dots? A simple linear express suggests a reliance on gamma. There's a lot more going on.

http://books.google.com/books?id=KKEOAAAAYAAJ&pg=PA174#v=onepage&q&f=false

Glrx (talk) 22:19, 5 September 2012 (UTC)

Acquired Dyschromatopsia

Any interest in adding a section on Acquired Dyschromatopsia? There is some tangential reference such a senile macular and diabetes however there's considerable research into the effects of neurotoxic solvents producing a tritan defect. Works by Donna Mergler at L'institute du travail in Quebec comes to mind.

Lanthony's D-15 and Farnsworth Munsel and Munsel D have become an intensive test on defining the range and extent of defect and dychhrom occular independence. Ken Bowman at university of Melborne (Syndey Australia) has produced a quantification system for determining the extent of CV defect.

Let me know if you'd like for me to contribute on this.

ALB--ALB (talk) 17:51, 3 September 2012 (UTC)

A radical proposal on "rainbow"

Were images derived from the gay flag more "correct" or less, but consideration about the perception of an SVG image (with some RGB colours, not real colours) are, generally, nonsense and at least a grave original research. So, I propose to throw away that gay flag (with its non-standard green and azure instead of blue) and its derived images and resort to a table which describes (relative) perception of standard colours, namely: white, red, orange, yellow, green, cyan (RGB cyan, CMYK cyan and spectral cyan slightly differ, but we can neglect it), RGB’s blue, and some of purple colors (such as magenta). Maybe, violet or indigo would be helpful too for tritanopia. Could we eventually find sources for standard colours? The table could look like the following. Incnis Mrsi (talk) 18:17, 31 August 2012 (UTC)

Color name:	white	red	orange	yellow	green	cyan	blue (RGB)	magenta (RGB)
RGB:	#FFFFFF	#FF0000	#FF8000	#FFFF00	#00FF00	#00FFFF	#0000FF	#FF00FF
Samples:
Protanopia:
Deuteranopia:								?
Tritanopia:

I'm sure these rainbows are better than the current versions on the front page. Even though I am a trichromat, my knowledge of colour vision tells me that any dichromat must be able to see a monochromatic white at a wavelength intermediate between the two cone central wavelengths. There is no logical alternative, given that white is the result of broad-band light, exciting both populations equally in the same manner as a suitaby chosen monochromatic wavelength. The existing rainbows only allow tritanopians to see a monochromatic white for some reason. The only reason that we trichromats don't see a monochromatic white is that there are no single wavelength that excites all three cone types equally (allowing for the ammplification of the SW cone output). PS, Even a protanopian ought to have a neutral band in the rainbow, as described above. Any dichromats (of any genetic sort) care to comment?

DJMcC (talk) 12:07, 12 September 2012 (UTC) I do see why tritanopia gives the brightest monochromatic neutral - it is the same reason that trichromats see yellow as the brightest monochromatic colour, that is it gives the highest overall cone cell signal, resulting as it does from the midway point between the red and green cone output curves. By the same token I would expect that deuteranopia would give the darkest neutral, because the two cone responses are the furthest apart in this case. DJMcC (talk) 12:36, 13 September 2012 (UTC) Another point on tritanopia. The rainbow shown in http://www.colblindor.com/2006/05/08/tritanopia-blue-yellow-color-blindness/ may be more realistic. Having said that, it appears from Digby's comment that he "could see green fine", that the green used in both Mrsi's rainbow and colblindor's may have too much blue in it, causing Digby (a tritanope) to see it as too dark to be realistic. Perhaps the green should be left as like trichromatic green, and blue as very dark "green". The portrayal of violet as dark red and yellow as white seem to be realistic. I understand the theory behind painting tritanope green as cyan/turquoise, but that surely only applies to trichromats. The subjective appearance of colours is ineffable in any case, so it's best to find colours that the dichromats themselves are happy with, however unbalanced that might seem to make the rainbow appear to trichromats. Hopefully the white still looks white to a dichromat, because it has to balance any two for a trichromat in any case. DJMcC (talk) 13:08, 14 September 2012 (UTC)

Implications of tritanopes' vision for trichromatic violet

The colour perceptions of tritanopes (who see violet as a dark red colour - http://en.wikipedia.org/wiki/Color_blindness#Classification), combined with the known spectral sensitivities of avian LW cones (http://en.wikipedia.org/wiki/File:BirdVisualPigmentSensitivity.svg), which show a second transduction peak at short wavelengths, throws light on why trichromats see violet as like a of mixture of red and blue - IMO, it really is a mixture of the red (LW) and blue (SW) cone signals. The problem with determining the spectral absorption of human cone cells is that they are only measured down to a wavelength of about 400nm (http://en.wikipedia.org/wiki/File:Cone-response.svg), so any weak, short-wavelength peak in the transductive part of the absorption spectrum gets truncated in the middle of the peak, and thus confused with non-transductive background absorption, which anyhow gradually rises throughout the range as the wavelength decreases, as shown in the plot. Of course, there would not seem to be any reason for measuring below 400nm, because the human lens strongly absorbs in the UV in any case. Direct measurement of specific cone cell response spectra would avoid this issue, but that is very difficult to do. DJMcC (talk) 11:12, 14 September 2012 (UTC)

Prejudice against colorblindness

Can't see an existing place to put this but perhaps someone who cares about this page might make a space.

http://www.aopa.com.au/infocentre/topicdocuments/colourvision.pdf

Colorblind individuals have been haphazardly excluded from aviation work for years without any scientific basis.

deadlink / maybe deep link at Aircraft Owners & Pilots Association of Australia / does arrive at their home page / searched as suggested at home page no luck JSo9-10 (talk) 10:52, 22 January 2013 (UTC)

"Blindness"

I hate the word blindness. You can call me color blind, but I do know what red or green is. I love painting and differentiate between light and dark red/green shades very precisely. People always mock at us, thinking we would have problems with traffic lights. For most of us, it's only the Ishihara color test which causes problems. I'm not allowed to become a pilot because I'm not able to see these stupid numbers? This is not fair!--89.14.84.180 (talk) 21:27, 22 September 2012 (UTC)

The photo of Neil Argbursen needs more info

There is a photo near the end of the article of someone with some head gear. The photo looks interesting, but the caption does not make clear who Neil Argburgesson is, what an eyeborg is, or how this is relevant to the article. Either the caption needs more info or should link to a page with more info. 129.63.129.196 (talk) 19:08, 28 December 2012 (UTC)

Try reading the last paragraph of "Management". Richerman (talk) 19:13, 28 December 2012 (UTC)

The only inprovement i can see here would be to lower the picture one line if i am looking a this correctly, then the last line of the last paragraph of "Management".

" Harbisson explained how he could now perceive colors... " would then show up directly under the pic in question. JSo9-10 (talk) 05:49, 22 January 2013 (UTC)

or move the pic up by two lines, not sure how to accomplish this, so...JSo9-10 (talk) 05:49, 22 January 2013 (UTC)

Unintended Cultural Bias

The first image on this article (1895 illustration) is literally flag waving. Could it be moved down? I would prefer that the first picture be culturally neutral and more sensitive to alternative regions. I have no objections to the picture itself which is extremely relevant. While all images may have a hint of bias, this image is blatant. Dpleibovitz (talk) 14:39, 18 January 2013 (UTC)

Very unintended i would say, please consider this article is in the am eng section of en_wikipedia, most likely writen by an english speaking american on this page it is spelled "color not colour" / or is there some other bias for your / "NOT SO SUBTLE / NOT SO PC QUESTION"... A figure (usually one or more Arabic digits) is embedded in the picture... jso an hour ago, see below for an hour later vvvvv amazing one hour

Looking at http://en.wikipedia.org/wiki/Wikipedia:Neutral_point_of_view/FAQ#Anglo-American_focus i may have WAY OVER REACTED TO YOUR bias question, sorry Dpleibovitz. Though you may be correct that the author is "flag waving", i (imho)still don't see it that way, i stumbled on this article years ago and have been watching it for signs that it is being added to in a responsible way, and as you see i was shocked / taken aback, by the bias question. When i looked at the flags i saw the history, nastoligia of "An 1895 illustration of normal vision and various kinds of color blindness" not a group of flags,so count me educated, i hope that others when they see a flag, any flag burning, they react as i did, then go "OH! Yes that is FREE SPEECH"JSo9-10 (talk) 07:59, 22 January 2013 (UTC)

Image

The image of the american flags at the top of the page is a little silly. Can this be changed to something less mono-cultural? — Preceding unsigned comment added by 12.233.9.72 (talk) 16:42, 22 January 2013 (UTC)

wrong statistic values?

In the table "Prevalence of color blindness" there is an "overall value" of 0.49 to 1% although the difference races have far lower values? Is this a typo? — Preceding unsigned comment added by 217.231.103.179 (talk) 14:42, 23 April 2013 (UTC)

I suspect someone became confused between percentages and straight decimals. Given how the unweighted average of the male figures is a little below the lower bound of the "overall" stat, and the unweighted average of the female figures is a little below ONE HUNDREDTH of the same - and there's information in the bodytext suggesting the "total" is correct - I propose that the individual "by race" figures need to be multiplied by 100. IE increased from 0.0016 ~ 0.0064%, up to 0.16 ~ 0.64% (or 0.0016 ~ 0.0064 when expressed as a decimal).

With appropriate checks made at the source, of course - along with sensible sanity checks and second-sourcing if that still looks suspicious and badly proof-read.

Alternatively it could be that there's a component of the global female population that's neither caucasian, african or asian, and makes up a high enough proportion of the total with a high enough instance of colour blindness to skew the overall result... 193.63.174.211 (talk) 08:42, 3 May 2013 (UTC)

According to Question from pp253, b) iii) 8% male redgreen color blindness, gives 0,64% in females.

Question: iii. (If mating is at random and red-green color blindness (which is sex/X linked) does not affect survival or fertility, what should be the proportion of color-blind women in a population at (Hardy-Weinberg) equilibrium in which 8 per cent of the men are color blind?

Answer: iii. Because male's are haploid for the X chromosome, q = 0.08. Since females are diploid for the X chromosome, their rate of color blindness in this population would be q2 = 0.0064 or 0.64%

Same conclusion in on page 5, 7.2 THE HARDY-WEINBERG PRINCIPLE) subsection 3) : 8% in males, gives 0.0064 = 0.64% in females.

I'll change the article.--Vbakke (talk) 23:01, 3 July 2013 (UTC)

edit request - classification: by cause: dichromacy: protanopia

This bit is rather strangely written, to whit the middle sentence:

" It is a form of dichromatism in which red appears black and therefore human can see light only from 400 nm to 650 nm. "

I wonder if this was machine translated from another language maybe? :) ... It also doesn't give any hint about the relevance of the wavelength figures, as they have hardly been discussed at all in the text up to this point.

How about:

"It is a form of dichromatism in which the subject can only perceive light wavelengths from 400 to 650nm, instead of the usual 700nm. Pure reds cannot be seen, instead appearing black; purple colours cannot be distinguished from blues; more orange-tinted reds may appear as very dim yellows, and all orange-yellow-green shades of too long a wavelength to stimulate the blue receptors appear as a similar yellow hue."

Or similar? 193.63.174.211 (talk) 08:35, 3 May 2013 (UTC)

Done precisely as suggested. (I'm trusting you on the facts here, on the general principle that people who can write clearly usually can think clearly.) Looie496 (talk) 16:01, 3 May 2013 (UTC)

Rainbow diagrams

Could these diagrams be removed? They aren't at all correct. — Preceding unsigned comment added by 80.189.80.23 (talk) 18:51, 31 May 2013 (UTC)

What is wrong with them, and what should be the correct diagram?--Vbakke (talk) 11:16, 31 July 2013 (UTC)

A root of the problem is commons:File:Gay flag.svg, modified back and forth for several years, to be chosen as the base of all these *anopia images. Later I tried to start a discussion, but it was dumped to an archive and forgotten. When I tried to fix some previous mistakes I likely introduced my own ones, but was reluctant to fix further due to insufficient feedback. Of course, if one can repair all this disorder, it would be great. Incnis Mrsi (talk) 11:36, 31 July 2013 (UTC)

I don't know enough to determine whether the flags are right or wrong. A simple step would be to delete the images because they are WP:OR or WP:SYN. We don't have a source telling us what the images should look like. We do have sources telling us how the 1895 flags and Ishihara plates are perceived. If there is a source for transforming color coordinates for different symptoms, then there could be a WP:CALC argument, but I don't think that is made in the current article. Glrx (talk) 22:13, 31 July 2013 (UTC)

I agree. If we keep them, we need to tie them to the specifications that created them. A bit of original work is OK in creating illustrations, but only if the underlying data are reliably sourced, I think. Dicklyon (talk) 23:33, 31 July 2013 (UTC)

Edit request on 9 August 2013

In the Further Reading section, please change McIntyre,D. John to McIntyre, Donald (this is the correct name; I've got the book) JimCaligari (talk) 21:11, 9 August 2013 (UTC)

Done. Glrx (talk) 22:15, 9 August 2013 (UTC)

Colourblindness in WWII

During WWII people with colourblindness were used on occasion to detect camoflage - there are a number of webpages on the subject (but for technical reasons I cannot call them up at the moment). Jackiespeel (talk) 14:33, 4 July 2013 (UTC)

You likely speak about deuteranomaly – technically it is not a color blindness, and it is rather common condition. Can you make an article about it? Incnis Mrsi (talk) 11:36, 31 July 2013 (UTC)

Not so much to "detect" camouflage, but to look at black and white photos of camouflaged items, in which they could see much more detail than non-colourblind people. Old_Wombat (talk) 12:25, 4 September 2013 (UTC)

Could see much more detail at black and white photos? It is an utterly ignorant speculation. Incnis Mrsi (talk) 20:17, 5 September 2013 (UTC)

Uhh, I thought it was self-explanatory, but obviously not. My understanding is that most WWII photography was black and white. Those "not coolourblind" (which may well be deuteranomaly) could not distinguish what the camouflaged objects were in these black and white images - that is, against them, the camouflage was successful. But those who were "colourblind", were not "fooled" by the camouflage, and could see what the camouflaged objects were. Are you saying that none of this is true?

Old_Wombat (talk) 10:50, 23 September 2013 (UTC)

My understanding of IM's criticism is once a black and white photograph has been taken, then any issue about color perception has been removed. There are no colors to perceive differently: everything is gray scale. On the other hand, it is entirely possible that real-life scenes or color photographs to contain camouflage that works with normal vision but fails with abnormal vision. Two pigments can be a color match even if their spectra vary widely. Glrx (talk) 20:49, 23 September 2013 (UTC)

Tritanopia and blue-yellow distinction

While Tritanopia is commonly referred to as blue-yellow color blindness, the statement that tritanopes cannot distinguish blue from yellow is wrong.

If you look at this image in the article:

Blue and yellow are clearly distinguishable (blue appears green, yellow appears pink). Tritanopia should more accurately be called blue-green color blindness, since tritanopes actually cannot distinguish blue from green. ANDROS¹³³⁷_TALK 16:23, 24 September 2013 (UTC)

The use of the rainbow flags is disputed; there's a perception issue; see above. That two particular monochrome colors can be distinguished is not surprising; shifting the colors slightly might find an isochrome. The rainbow flag colors were not chosen to highlight abnormal vision. Diagostic tests for symptoms do not used saturated colors. Glrx (talk) 23:04, 27 September 2013 (UTC)

The problem is that there are no actual yellow cones in the human eye; Tritanopia is the lack of blue cones, and thus everything is seen in shades of red and green. Based on the image, it appears the red cones are more sensitive to yellow, while the green cones are more sensitive to blue. I personally think the term "blue-yellow color blindness" was named for the sake of completeness, and for the fact that tritanopes cannot see (NOT distinguish) the colors blue and yellow. ANDROS¹³³⁷_TALK 20:05, 7 October 2013 (UTC)

FYI, I went ahead and made my suggested corrections (WP:BOLD). ANDROS¹³³⁷_TALK 22:23, 30 October 2013 (UTC)

Andros' edits, from his comments above, sound in WP:OR. I'm tempted to revert since additions change some meanings and do not have sources. Several google hits repeat trianopes cannot distinguish blue and yellow. (eg, http://www.britannica.com/EBchecked/topic/605982/tritanopia) Glrx (talk) 00:23, 10 November 2013 (UTC)

This is a common misconception due to the common name of the condition. And Britannica isn't any more reliable than Wikipedia. If you look at the image, blue and yellow are obviously distinguishable. Remember that the L (red), M (green), and S (blue) cones are not sensitive to any specific wavelength; they cover a continuous range of wavelengths. The L cones are more sensitive to long wavelengths, M cones to middle wavelengths, and S cones to short wavelengths. There are no discontinuities in the range of wavelengths that that each cone can perceive, therefore it isn't scientifically possible that a tritanope can distinguish blue from green but not from yellow, since green is closer to blue on the spectrum than yellow is. Based on the image, the L cones are more sensitive to yellow, while the M cones are more sensitive to blue. Perhaps if the shade of yellow had more green in its hue it could perhaps appear greenish to a tritanope . ANDROS¹³³⁷_TALK 21:46, 10 November 2013 (UTC)

Editing Evolutionary arguments section

I'm improving the Evolutionary arguments section for a class assignment, and my edits are currently in my sandbox. Before I post it, I was hoping to get some constructive criticism on my additions and edits. Thank you! Larry.monocello (talk) 23:51, 22 October 2013 (UTC)

When making a request like this you need to give a link to your sandbox. I'll leave some comments on the sandbox talkpage. Richerman (talk) 13:15, 23 October 2013 (UTC)

I've uploaded my edits. There was a section about macaques in this area that didn't really fit, and also wasn't well sourced, so I deleted it. — Preceding unsigned comment added by Larry.monocello (talk Larry.monocello (talk) 17:04, 12 November 2013 (UTC)

User:Larry.monocello who added this is in user:Sanetti's Darwinian medicine class. I looked over what you did and it seems entirely appropriate and useful. You found multiple sources which backed the content you added, you learned the wikitext markup and formatted everything properly, and you took initiative in modifying existing text. Thanks. It seems like you are expecting your classmate to review this further - I expect that to be even more productive. Blue Rasberry (talk) 14:40, 20 November 2013 (UTC)

Removing for evaluation of WP:UNDUE and WP:MEDRS. SandyGeorgia (Talk) 13:41, 21 December 2013 (UTC)

Evolutionary considerations

The following hypotheses explore the role of evolution in dichromatism via explanations from evolutionary medicine.

• Adaptation: During the Second World War, the US Army discovered that colorblind soldiers could distinguish camouflaged targets better than their counterparts with color vision could. Further studies have shown that dichromats are better at detecting camouflaged targets in which the object’s color accounts for differences in texture between the object and its surroundings, have sharper vision, and may be less subject to the effects of “chromatic noise.” Other studies suggest a dichromat advantage in mesopic vision and scotopic vision. There is also a hypothesis that X-linked color deficiency leads to better discrimination against blue backgrounds, conferring an advantage to dichromats in fishing. As a result, dichromats may have an advantage over trichromats in detecting some kinds of prey, which could explain higher rate of dichromatism in relation to other defects.

• Evolutionary Legacy: Another hypothesis posits that the high frequency of dichromatism in humans is due to a relaxation of pressure for trichromats in societies that have been traditionally pastoral and agricultural. Because color vision is less important to survival in these societies, positive selection for trichromatism would be relaxed. Because the only genetic difference between a dichromat and a trichromat is in the opsin genes, in agricultural-pastoral societies the ancestral dichromat phenotype not being a reproductive hindrance (and therefore not being subject to negative selection)—but rather the newer trichromat phenotype merely being more advantageous in pre-agricultural societies (subject to positive selection)—accounts for the relatively high frequency of dichromatism in these societies.

Test image removal

I suggest that we remove all the test and "how things look" images except the Ishihara plates and other public domain images from reputable sites. We don't know how well they actually work and their construction is in essence a form of oiginal research. Mangoe (talk) 13:59, 30 January 2014 (UTC)

I agree. I have color blindness and all the images look different to me on these "how things look" comparisons, so they don't even work. --Connelly90[AlbaGuBràth] (talk) 11:08, 31 January 2014 (UTC)

• Support. See Talk:Color blindness/Archive 1#Rainbow diagrams. There's also an issue of perception rather than just color matching. Glrx (talk) 20:44, 1 February 2014 (UTC)

The article is entirely human-centric

There really ought to be at least a brief discussion of the point that most mammals are normally dichromats (primates being the exception). --71.62.74.115 (talk) 20:24, 26 May 2014 (UTC)

Color-Blind Male and Color-Blind Female Procreate

The article states:

"Should an affected male have children with a carrier or colorblind woman, their daughters may be colorblind by inheriting an affected X chromosome from each parent."

Wouldn't two color-blind people be certain to have color-blind children, or would they have to have the same type of color-blindness?

Mikevegas40 (talk) 21:33, 13 November 2014 (UTC)

Colorblind, Color-Blind or Color Blind?

I have seen color blind, color-blind and colorblind used. Meriam Webster goes with color-blind. So does Oxford in its American English online version.

Mikevegas40 (talk) 21:33, 13 November 2014 (UTC)

Rename article to "Color vision deficiency"

The article should really be renamed to "Color vision deficiency" and "Color blindness" redirect to it. As stated in the article it is more common to be deficient in color vision, but not lacking it! Therefore color blindness (not perceiving colors at all) is a special/maximum case of color vision deficiency. Using color blind for describing a condition with a broad range is a very unprecise top-level term, derogatory, and perpetuates ignorance.

Thanks for considering the renaming.

Support The book Ophthalmology by G. Lang also describes it as color vision deficiency and not as color blindness. So I agree, it should be moved.--Michael (talk) 11:45, 12 October 2014 (UTC)

Support Although colour blindness is the common name used for various colour deficiencies it is inaccurate and perpetuates the idea that all those with a deficiency can't see particular colours, or indeed or any colours. Richerman (talk) 12:07, 12 October 2014 (UTC)

• Oppose reluctantly. The WP:COMMONNAME for the deficiency is color blind. The person on the street would search for CB rather than CVD. WP wants the common name to be used (WP "prefers to use the name that is most frequently used to refer to the subject in English-language reliable sources"); that preference can be overridden if reliable sources find the common name to be "inaccurate" or non-neutral ("as determined in reliable sources"). I do not see the term to be so inaccurate that it should be overridden; I understand CB to be the deficiency rather than color+blind; the term often has modifiers such as red-green color blind. The WP article says CB is imprecise ("There is no actual blindness but there is a deficiency of color vision"), but where are the reliable sources saying the term is so inaccurate/objectionable that it should not be used? Even articles that use CVD point to color blind: http://www.colourblindawareness.org/colour-blindness/living-with-colour-vision-deficiency/ says CVD but the website domain name embeds CB. NIH online encyclopedia uses CB;[8] the alt names include "color deficiency" but not "color vision deficiency". See also http://ghr.nlm.nih.gov/condition/color-vision-deficiency/show/MedlinePlus (uses CB); compare to genetics http://ghr.nlm.nih.gov/condition/color-vision-deficiency (uses CVD). I'm sympathetic to the change, but right now it seems more prescriptive than descriptive. Glrx (talk) 17:41, 17 October 2014 (UTC)
• Oppose Per WP:COMMONNAME. HiLo48 (talk) 21:37, 13 November 2014 (UTC)
• Oppose reluctantly as well. Structure of article could perhaps be used to forward the goal of greater use of the term Color vision deficiency, but that has yet to achieve common usage and would not be searched for. Per WP:COMMONNAME. [ comment added by Eyesup1 (talk • contribs)

Epidemiology: Prevalence of color blindness table

The Epidemiology section suggests there is regional variation in the incidence of color blindness. It is not clear whether the information in the present table is for the world or for a particular country or region (and the source from which the table is copied is silent on this). It would be useful instead to have a table illustrating the regional variation, if there is a good source for such information. --Frans Fowler (talk) 06:46, 27 December 2014 (UTC)

Adding of 4 Citations to help credibility of article

1. Updated a source in the background about statistics of those color blind 2. Added in a sentence in Anomalous trichromacy section to give readers better understanding of its relevance in comparison to other types of color blindness with a notable source. 3. Added in a notable source about Ishihara color test 4. Added source to Design Implication section

JulieEng2000 (talk) 04:11, 20 February 2015 (UTC)

Image Problem

For the sake of pluralism please remove the U.S.A. flag and put another more appropriate image, since this is a scientific topic I consider that no political topics, imaginery or symbolism must be used. Thanks. I recommend the image of the reference , which is creative commons free and shows better the different color blindness problems. — Preceding unsigned comment added by 190.193.41.99 (talk) 15:24, 28 February 2015 (UTC) |I agree with you. Why don't you do it?--Michael (talk) 10:04, 9 March 2015 (UTC)

References

Colorblind people who read this article

How are colorblind people like me supposed to understand the difference between the pictures of apples? The pictures showing how a colorblind person would see the apples are intended for people with normal vision. For me, I can clearly see the left apple is red and the right one is green. And the pictures beneath show them with brownish tones. Am I even considered colorblind? I know there are different types (I'm talking about the red-green one), but are there degrees of color blindness? I have no problems with distinguishing red from green except that I fail to see the numbers in those pictures, which have no practical use in everyday life. --2.245.220.72 (talk) 21:06, 17 March 2015 (UTC)

Yes there are degrees of color blindness, and yes if you can't see the numbers then you have a form of color blindness indeed, but probably not severe enough as to interfere with your life. For more info you can probably read this site, it's very interesting http://www.color-blindness.com/ --Krystaleen 03:50, 18 March 2015 (UTC)

spectrum-notching eyeglasses

Are these novel enough to merit space? Any experts?

Possible text: More recently, spectrum-notching eyeglasses have been developed ; like tinted glasses, they cut out some spectral frequencies, but in a narrower, sharper-edged frequency range . — Preceding unsigned comment added by HLHJ (talk • contribs) 15:38, 24 February 2015 (UTC)

References

Related: The Avegant Glyph team a non-VR DPL-based HMD claimed similar results with their display. 00:22, 28 March 2015 (UTC)

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Animals?

The one question I had coming to this article remains unanswered. Orthotox (talk) 19:06, 3 October 2015 (UTC)

main picture: let's find a better one!

Color blindness

I recently changed the main picture (the one with the flags) to the one here to the side, only to have it reverted back soon after. I think the picture of the flag is not a good choice to illustrate this page. I saw that this issue has been discussed at least another couple of times in the archives of this talk page, but I don't think any consensus--let alone a solution--was reached.

I do think the picture of the flags has an important value in describing the history of our understanding of this vision deficiency, and I would keep it to the Background section of the page. However, this is not the image I would expect to find in the encyclopedic entry on color blindness. Just do a quick search for color blindness and you see that results fall mostly in three categories (more or less in order of prevalence in the top search results):

• 1 color blind test (of which we already have plenty in the article;
• 2 color spectra or color palettes modified to represent what color blind people would see (basically the image I proposed and the like).
• 3 the way in which some colorful images would look to color blind people (like the flag, but in my opinion a traffic light light is way more representative, if we want to stick to this category).

I hate revert wars, but I do hope that this would spark some discussion and hopefully a better illustration for this page.

PS. Just a joke: if we really want to keep the picture of a flag, let it be a peace flag... it would be more or less like combining 2 and 3 from the list above together! — Preceding unsigned comment added by Japs 88 (talk • contribs) 13:05, 30 September 2015 (UTC)

Is there an RS for your image? Do you have any sources about how color blind people perceive an image? Earlier flag pictures were knocked out for that reason. Glrx (talk) 18:40, 1 October 2015 (UTC)

I just want to second that the flag picture is bad and I came to the talk page solely because I saw it and wanted to say it should be changed.

First, it's such a poor understanding of colorblindness (as "you see a specific color as black") that I'm skeptical as to whether it even fits in "history of scientific understanding of colorblindness", because it looks like the result of someone who heard "some people can't see colors" and guessed at the actual mechanics based on that one sentence, not the result of any sort of interaction with actual colorblind individuals.

Second, even for those standards it's a terrible representation: it A: chooses an object with no Green present, B: presents it in different orientations and arrangements for no reason, and C: contains shadows when the point of the image is to compare different colors with black. I personally thought all but the no-color flag were normal American flags until I looked closely! (slight confounder in that I'm red/green colorblind, but I couldn't tell that the blue was black on the back one any more easily) 140.232.157.167 (talk) 21:57, 2 October 2015 (UTC)

Ok, RS problem solved. I created an svg image ad hoc from an article about colour blindness. Going to place it in the article. --Japs 88 (talk) 09:42, 3 October 2015 (UTC)

No, it is not solved. The figure does not match descriptions given in the WP article; e.g., tri.

There's also a fundamental issue here. That someone can distinguish two colors does not mean that he perceives the colors the same way one with normal vision does. Say the shortwave sensors are gone; in essence, the blue channel is gone. One can still distinguish shades of blue by variations in the other channels. That does not mean such an individual perceives (gets an image in his head that appears to be) blue.

One can certainly choose a color pallette whose colors have large deltas even for people with color vision dificiencies.

Furthermore, one cannot recreate images from copyrighted works and claim them as his own.

Glrx (talk) 17:12, 3 October 2015 (UTC)

First, my version of the palette is sufficiently different from the published version (which is explicitly cited on Commons) not to infringe on anyone's copyright: I changed shape, layout, background (to a much better 50% grey), the names of the vision deficiencies are in the image, etc.

Second, your "fundamental issue" above does not exist: the image is based on a recent scientific publication which clearly states that those are the colours as perceived by people affected by subject affected by those specific types of colour blindness. This is in contrast to an illustration of a book from 1895! If you don't agree with the source I am using to base my illustration on, please cite the original reference that your statements are based on.

Assuming good faith, maybe the problem is that I wasn't precise enough in the caption...English is not my first language, so feel free to improve it. That said, I'm going to revert to include my illustration. Indeed, there is still room for improvement, but in my opinion it is already quite a leap forward with respect to a greenless US flag illustration from 1895.

--Japs 88 (talk) 11:23, 4 October 2015 (UTC)

black and white

Quick question: is there any form of colour blindness that involves only seeing black/white? — Preceding unsigned comment added by 87.211.43.32 (talk) 16:30, 21 November 2015 (UTC)

Yes, Achromatopsia which is talked about under the title Total color blindness - but to be precise they perceive black, white and shades of grey. Richerman (talk) 21:05, 21 November 2015 (UTC)

Spurious citation request?

Why is there a request for a citation about the statement, "Should an affected male have children with a carrier or colorblind woman, their daughters may be colorblind by inheriting an affected X chromosome from each parent.", in the Red-Green color blindness section? If both parents carry the red-green mutation, then there must be as a matter of pure mathematical fact be up to a 1:2 chance of producing a color blind daughter. The male can only give the mutation X, and the mother recombines her 2 X chromosomes, and the mutation may or may not be passed along in the X she gives. It's not a straight linear probability because of recombination. On average in a large population and many children it will yield a 1:2 probability. 173.24.40.128 (talk) 14:32, 23 December 2015 (UTC) [celtic_hackr not logged in]

Assessment comment

The comment(s) below were originally left at Talk:Color blindness/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

In WP Medical genetics

Last edited at 16:10, 27 August 2006 (UTC). Substituted at 20:20, 2 May 2016 (UTC)

Improving the section on "Frequency of red-green color blindness in males of various populations"

The section on "Frequency of red-green color blindness in males of various populations" could be improved with a little narrative and possible some confidence intervals and a plot. If "N" in that table is the number of people sampled from the indicated country and "%" indicates the proportion of those with red-green color blindness, as seems implied, then it's a relatively straightforward matter to compute a 95% confidence interval for each country. I say "relatively straightforward", because there are at least a dozen different procedures that give slightly different answers. A recent comparison with software is available with the "proportions" and "binom" packages for the R statistical programming language from the Comprehensive R Archive Network. Fortunately, there is a vignette for the "proportions" package that compares the different procedures. Without reviewing that, a reasonable approach (if not the best overall) uses the logit transform.

I'm not prepared to do the research to confirm that these numbers mean what they appear to mean. However, if someone else can confirm that, I can compute confidence intervals, add them to the table and add a plot, showing the estimates with confidence intervals. I might also provide a plot to use either in addition to or in lieu of the table. DavidMCEddy (talk) 04:09, 3 February 2016 (UTC)

The relevant reference is available dirt cheap if you want to look; no preview on GBS, sadly. Dicklyon (talk) 04:24, 3 February 2017 (UTC)

Tetrachromacy rate

I've removed this bit of text:

If the incidence of red-green color blindness is 8% in males of North European origin, then the carrier frequency (i.e. tetrachromacy) among the females of that genetic stock is 14.7% (= [92% x 8%] x 2).

It's incorrect to calculate Hardy-Weinberg equilibrium based on total rate of red-green color blindness, because that lumps together four different alleles at two different loci. It's incorrect to equate carriers with tetrachromats for the same reason: To be a tetrachromat, a female needs to be heterozygous for both protanomaly and deuteranomaly, which will be much much rarer than carrying either one.

Yes, I know it's cited. In a single source, a textbook from 1988. Sometimes textbooks are wrong, and sometimes Wikipedians misunderstand them. I'd be happy to do the correct Hardy-Weinberg calculations myself, but in case someone decides that doing arithmetic is "original research" and gets humpy about it, we should have a citation if we can. eritain (talk) 07:02, 9 March 2017 (UTC)

Hi Eritain. I am happy to leave your edit unaltered, as the situation might not be as simple as my original statement suggests. But I would like to suggest that the mathematics (Hardy-Weinberg equilibrium) I applied is perfectly correct and appropriate in the this situation (where "prefect" and "appropriate" mean as accurate as the available data allow). Firstly protans (protanomaly and protanopia) are very rare (not more than 1% of the male population each), which means that the vast majority of red-green colorblind persons are deutans (deuternanomaly and deuteranopia). The frequency of deutans is variously quoted to be between 5 - 8% of males of north west European descent. So using 8% (or any percentage between 5% and 8%) as the incidence of "red-green color blindness" gene could mean the incidence of both deutans and protans, or just of deutans, without loss of any meaningful accuracy. Secondly for a woman to be tetrachromatic she would have to be heterozygous for either protanomaly or deuteranomaly. Not both. If she were heterozygous for both she would be pentachromatic (two varieties of red receptors, two of the green receptors, plus one of the blue!).

However it is necessary to ascertain whether, in these potentially tetrachromatic and pentachromatic women, each of the 4 or 5 different types of cones in the retina has its own neural channel to the occipital cortex, or not. It could easily be that the two varieties of red receptors in the person who is heterozygous for protanomaly share the same neural pathways, and are interpreted as one single type of signal about the color of an object; and similarly the heterozygote for deuternanomaly. However, Jameson et al. have found evidence that women who are heterozygous for deuteranomaly do in fact have great color discrimination than normal trichromats, but that the degree to which they benefit from their tetrachromacy seems to depend very much the type of deutan gene they have inherited. So the evidence seems to show that in heterozygotes (whose frequency in any given population can be calculated very simply - there is nothing more controversial about the Hardy Weinberg calculation that those of Newton's laws of motion - the cones with the different color pigments have separate channels to the cortex. Cruithne9 (talk) 15:39, 19 March 2017 (UTC)

PS. I notice that the incorrect statement that tetrachromacy is caused in women by being simultaneously heterozygous for BOTH protanomaly AND deuteranomaly occurs in the text of the article. This is quite clearly not true, as explained above, and by Jameson et al.. It is necessary for her to be heterozygous for only one or the other to be tetrachomatic (e.g. the deuteranomalous heterozygote has, in her retina normal long wave receptors, normal medium wave receptors, the abnormal medium wave receptors and the normal autosomal short wave receptors). If she is heterozygous for both protanomaly and deuteranomaly she would be pentachromatic. I will change the incorrect paragraph. Cruithne9 (talk) 07:23, 25 March 2017 (UTC)

PPS. Now that I understand why Eritain was worried about the calculation of heterozygous deuteranomaly (and therefore potentetial tetrachromacy) in women of north European descent using the Hardy Weinberg equation, and have dealt with that confusion, I am going to re-instate that statement so that the reader is given an impression of how many women are potentially tetrachromatic. I'm sorry Eritain to go back on my word that I would leave your deletion unchanged, but hopefully you will agree that it is not inappropriate. (Please change it back if you are uncomfortable with it). Cruithne9 (talk) 15:13, 26 March 2017 (UTC)

Rv "This deficiency does not cause difficulty discerning red from green"

I am removing a sentence ("This deficiency does not cause difficulty discerning red from green") as unsourced and implausible. It was inserted by 2601:240:8200:ACAF:D8A3:4A48:FE64:93FE (at 18:27 on 14 February 2016) adjacent to two refs that pertain not to this but to a different proposition in the previous sentence. One of those refs (Wong, Bang 2011) is behind a paywall; the other (Neitz, Jay; Neitz, Maureen 2011) does not appear to support the proposition that red–green color blindness does not cause difficulty discerning red from green. --Frans Fowler (talk) 17:07, 28 May 2017 (UTC) (deuteranomalous)

Epidemiology

While the textual part of this section is quite clear and documented, it is then followed by a table titled "Red–green color blindness" which I find quite mysterious. It has 3 entries: Population, N, %. Population and % are clear, but what is N? It might become clear if one could get access to the cited source, but I cannot. So, who can grab that Harrison book, please clarify this table, either by replacing N with some clearer label, or by adding a sentence or 2 where the meaning of N is defined. Thanx in advance! Nicola.Manini (talk) 15:14, 23 September 2017 (UTC)

N means the number of people studied User:Nicola.Manini Doc James (talk · contribs · email) 19:34, 23 September 2017 (UTC)

Mexicans or Navajos

Can anyboy access the source for the male prevalence table?

I'm very suspicious of the fact both Navajos and Mexicans have a prevalence of 2,3% out of exactly 571 individuals studied. It really looks like they studied 571 Mexican Navajos, and added it twice to the table. --77.230.216.174 (talk) 18:07, 1 May 2018 (UTC)

Epidemiology in males

When the current epidemiology section was added it was correctly titled "Frequency of red-green colour blindness in males of various populations". Now it said (wrongly) it was refering to the general population. The change / vandalism was by user Doc James. --77.230.216.174 (talk) 21:44, 29 April 2018 (UTC)

Per Wikipedia:Manual_of_Style#Section_headings it says "Headings should not refer redundantly to the subject of the article (Early life, not Smith's early life or His early life) or to higher-level headings, unless doing so is shorter or clearer."

Frequency is thus not needed as that is included within epidemiology.

Females could also be discussed in that section. Doc James (talk · contribs · email) 06:03, 30 April 2018 (UTC)

Whenever possible, it makes sense to assume good faith. From my perspective, based on the edits and articles I've seen, Doc James works very diligently to keep articles clear, accurate and spam-free. Arllaw (talk) 17:52, 2 May 2018 (UTC)

Red and green apples image - 'Citation needed' tag removed

I have removed the following tag from the caption of the red and green apple simulation image:
{citation needed|date=May 2015}<!-I am Deuteranomaly and these are totally differn't. user:scientus->.
The proposition illustrated by the simulation is sourced in the body text; the source of the image is given in the media description. Moreover, the image is supposed to illustrate normal v. dichromatic perception, not normal v. deuteranomalous perception, and it isn't clear from scientus's hidden remark what is "totally differn't" from what.
As it happens, my own sight is strongly deuteranomalous, and in a way the simulation works perfectly for me: the top pair looks exactly like the bottom pair — as one would expect for someone with dichromatic vision.
--Frans Fowler (talk) 14:17, 31 May 2018 (UTC)

Medical Condition Infobox entry for Symptoms

In the Medical Conditions infobox, in the description for Symptoms, it states: “Decreased ability to see colors” There is a reference attached in support of that description linking to the National Eye Institute: https://nei.nih.gov/health/color_blindness/facts_about I do not think the reference supports the description. I understand the range of colour deficiencies that are collectively termed Colour Blindness. But I do not think this description for the symptoms of colour blindness is accurate or sufficiently precise. I have selected two sentences from the first paragraph from the reference that I think contradict the infobox description: 1. Some people, however, have a color vision deficiency, which means their perception of colors is different from what most of us see. 2. People with color blindness aren’t aware of differences among colors that are obvious to the rest of us. I think the language used by the National Eye Institute is considerably more precise than “reduced ability to see colors”. It describes a difference in perception of colour, and awareness of differences among colours. The most common forms of colour blindness, relating to red-green colour vision, are much more subtle than “ability to see colours”. Colour blindness is probably the most misunderstood vision-related defect there is, and a description of “reduced ability to see colours” just feeds common misapprehensions. I didn’t just go ahead and change it because I’m a deadset newbie to editing WP, and it seems like a major change to mess with things in infoboxes. Any feedbank would be appreciated. Prime Lemur (talk) 17:44, 7 July 2018 (UTC)

"Reduced ability to discriminate certain colors" might be closer to the mark. Alternatively, throw out the concept of it being a medical condition; it's really just a part of a range of normal genetic variation. Dicklyon (talk) 18:02, 7 July 2018 (UTC)

Association football and colour blindness

There's an interesting discussion of colour blindness in relation to association football here: World Cup 2018: Why millions of fans see the football like this JezGrove (talk) 22:59, 14 July 2018 (UTC)

Strange article. Did he never watch black and white TV? (Or is this a young person's problem?) One team has white shorts. The other dark green. They couldn't look more different! HiLo48 (talk) 23:08, 14 July 2018 (UTC)

Questions for an expert on the subject

Re those with only one of the three cone systems working properly:

1. It appears from the statistics in the article that the number of such cases in the population is not insignificant, so this category should be fully covered in the article. Agree?

2. It seems illogical to descrbe this category as achromatopsia. Agree?

3. It would seem to me that this category ought to have some residual colour distinction, based on the ratio of the amounts of light detected by (a) the rods, and (b) the one remaining category of cones. Agree?

---

Ehrenkater (talk) 18:45, 20 July 2018 (UTC)

Responses:

1. We should cover whatever we have sources for, whether the numbers are significant or not.

2. "Achromatopsia is a condition characterized by a partial or total absence of color vision." It seems that having only one cone type would likely cause this condition, but go by what sources say.

3. Some residual color distinction is possible, but I would think not particularly likely, since there's only a limited intensity range over which both the rods and the cones would provide information, and the usual "opponent" system of color encoding and interpretation might not be able to develop under such conditions. Dicklyon (talk) 16:47, 23 July 2018 (UTC)

Dicklyon (talk) 16:47, 23 July 2018 (UTC)

Ambiguous

"Adjustments to teaching methods, mobile apps". What specifically does the "mobile apps" mean? Does it mean using using special mobile apps to aid others, or what specifically? The article is unclear on this fact. Qwertyxp2000 (talk | contribs) 22:34, 9 August 2018 (UTC)

Anecdotal

I'm sorry I lack evidence, but a friend who was colorblind (at least in the red area of the spectrum) was deer hunting and shot a deer. We helped him track a blood trail using a red light source intended to emphasize blood drops. At some point, the friend/hunter declared "I'm seeing colors I have never seen before." I trust that he was not kidding, as he was quite amazed and history of color-blindless well known to his friends. Is there an explanation for this phenomena? Sorry I don't know anything about the emission spectrum of the blood tracker. 2600:6C48:7006:200:D84D:5A80:173:901D (talk) 02:05, 16 August 2018 (UTC)

Famous colour blind artist

Clinical and Experimental Optometry has an article showing that Clifton Pugh on biographical, inheritance and other grounds was was a protanope. I have looked hard but cannot see any place suitable for this information in the article. There is no section for "notable color blind people" though such sections exist for example for Prosopagnosia. I have put this information with reference (more details are in the online abstract) in Color blindness and occupations though this is not the ideal place. However the information is important since it shows that color blindness should not stop people for seeking to become artists if that is their talent.

I was watching a scientific video in which they explained color blind people also see a certain color that others don't... I was curious about that, but see it nowhere here David Lemire (talk) 01:10, 20 March 2019 (UTC)

Multi refs in the lead

None of it is really controversial. One ref is sufficient. Rest can go in the body. Doc James (talk · contribs · email) 11:11, 7 May 2019 (UTC)

"Deuteranopia sight" picture

For the "Deuteranopia sight" picture, shouldn't it be "Protanopia sight" instead?

The picture seems like the red hues are missing, while the table in the "Types" section associate the lack of red hues with Protanopia, not Deuteranopia (associed with the lack of green hues, which are perfectly visible, to me) — Preceding unsigned comment added by Prometheos2 (talk • contribs) 02:32, 29 May 2019 (UTC)

Different Types of Achromatopsia

I assume the label is referring to the 2 types of monochromacy. The article itself implies that achromatopsia means only rod monochromacy, but I think it normally means any monochromacy. I am not an expert, but I think I know the missing information to clarify the difference between the two. No main cause is given for cone monochromacy. This is caused by only a single type of cone being functional. The second sentence is nonsense, or at least a garbled version of the truth. Of course, if two different cone types are missing or non-functional, that only leaves one, but that does not mean that monochromacy is a combination of two types of dichromacy. It is certainly not an additional cause to a (missing) main cause, as implied.

I think it would also be useful to link the symptoms of rod monochromacy to the cause. If no cones are functional, vision is still possible using the rods, but these are for night vision and overload in bright light.

Unfortunately I do not have any reeferences to justify my opinion, so I have not made an edit. Where are the Facts (talk) 17:57, 25 February 2020 (UTC)

Why some contries

I am just intrigued by the fact that a article in Wikipedia are referring to British countries, Canada and USA. I am thinking of removing such references in a generic article. --84.210.141.97 (talk) 13:22, 24 March 2020 (UTC)KES

Diagnosis

In the Diagnosis section of the article, there appears to be a missing word: "... simplified to six tests; test, one of tests 2 or 3,... " should likely read " ... simplified to six tests; test 1, one of tests 2 or 3, ..." SquashEngineer (talk) 18:19, 23 April 2020 (UTC)

Tritanopia

The text in the article is not correct despite cited sources saying the contrary. Even though blue-yellow color blindness is the common name, in truth Tritanopia should be called blue-green color blindness since it is actually green (not yellow) that is indistinguishable with blue. Yellow appears pinkish (not blue or green) to people with tritanopia, and this is due to L/M vs. S cones and the laws of physics. This should be corrected ASAP. ANDROS¹³³⁷_TALK 22:52, 29 September 2020 (UTC)

Main chart

The treatment and frequency sections of the graphic seem severely lacking, and should probably be elaborated on. WikiWonder159 (talk) 05:41, 17 July 2021 (UTC)

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 14 January 2021 and 16 April 2021. Further details are available on the course page. Student editor(s): Jameskyp.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 18:04, 16 January 2022 (UTC)

Common Medical Nomenclature

Is "color perception difference" more accurate terminology than "color blindness" or "color vision deficiency" when referring to color vision syndromes beyond complete achromatopsia?

Do English-language textbooks of Ophthalmology and Anatomy & Physiology currently reflect this?

Dasuitts (talk) 16:37, 17 January 2022 (UTC)

"Mechanism" section does not actually contain the mechanism for color blindness..

it contains some references to how tricrhomic color vision works, but no indication of the mechanism(s) behind color blindness. — Preceding unsigned comment added by 192.184.131.199 (talk) 17:56, 7 May 2022 (UTC)

I agree with this critique and made an attempt at updating the section to be more in line with explaining CVD, i.e. the deviation from trichromatic vision, not trichromatic vision itself. I still need to fill in the blanks with some sources. Curran919 (talk) 14:34, 3 June 2022 (UTC)

Merger with Color Anomaly

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

no objection to merge. Felix QW (talk) 19:11, 19 September 2022 (UTC)

---

I propose merging Color anomaly into Color blindness. The page should - if anything - be called anomalous trichromacy, but I do not think it warrants its own page like dichromacy and monochromacy do, since the scope is much narrower. The current content is fully redundant with what is already in Color blindness, and I would say potential content (e.g. if I really felt like filling out an anomalous trichromacy page) would be 90% redundant. On the flipside, I don't think making a page for anomalous trichromacy would allow significantly less information on Color blindness. I think the OP made that page, since many object semantically to color blindness being used to include "partial" color blindness, but that is how it is both in literature and colloquially.Curran919 (talk) 11:55, 6 June 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Split for Color Vision Standards

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

split was carried out under new title color vision tests Curran919 (talk) 22:56, 8 October 2022 (UTC)

---

I'm considering splitting much of the content (and potential content) of the diagnostics section into a separate article outlining the different types of color visions tests and standards which are only very lightly covered here. Thoughts? Curran919 (talk) 14:46, 1 June 2022 (UTC)

• Support – technically, there is no such thing as a colorblindness test. They are all color vision standards. This is like saying an IQ test is a "genius test" or an "idiot test". Many color vision standards are not even used for color blindness. This is a much needed distinction, and will give a good place to expand on some of the color vision standards that are currently their own stubs, like City university test. Curran919 (talk) 15:56, 11 September 2022 (UTC)
• I had close this discussion, but patroller wants some more input, so I'll see if I can get some other comments.Curran919 (talk) 20:50, 19 September 2022 (UTC)

I moved this back from the archive so we can discuss. Dicklyon (talk) 21:26, 25 September 2022 (UTC)

I don't know much about the color vision tests and standards here; it's unclear to me whether there's enough for a standalone article or whether it would be good to keep the material under color blindness, assume that's what the test are mostly about. So far I'm neutral on the proposal. Are these things really called "color vision standards"? Where? It looks to me like the "standards" are about what "tests" to use in various situations. Dicklyon (talk) 21:26, 25 September 2022 (UTC)

Color vision standards would be the proper metrologists's term [9][10][11]. A standard is a benchmark plus a method for comparing to that benchmark (the test). Obviously the "tests" cover both aspects. Anyway, it's the 'color vision' part of the title (as opposed to color blind) that I am firm on, I'd agree to go "color vision tests" to be more colloquial.

Another reason I wanted to split this is I saw 3 or 4 instances of "color vision test" being directed to Ishihara test, even though used in the general sense. There are also some stubs like City university test that I don't think deserve their own article, but I would not both putting in color blindness. The only tests that should probably (and do) have their own article are the Ishihara test, D15/100Hue, Anomaloscope and FALANT, but I do have a lot to expand on in the article (see major topical sources I've read recently [12][13]). There are many popular tests that are either too historical (Holmgren's wool) or have less "tenure" than the others (HRR, CUT, CAD, Rabin CCT) to warrant their own article, but deserve a presence, especially the ones that are actively used as standards. Plus, a basic mechanism of how the tests work is warranted, but TMI for color blindness. I thought I would worry about expansion after the split, but do you think I need to do that first? Curran919 (talk) 07:20, 26 September 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Split for Genetics of Red-Green Color Blindness

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

I am canceling my support for this split, since it doesn't address the main problem with the article: a conflation of "colorblindness" as a generic symptom of many conditions (dischromatopsia) and "colorblindness" as a genetic condition usually referring to red-green color blindness and often called Daltonism, especially in other languages. I will make a separate discussion on how these elements can be separated.Curran919 (talk) 20:30, 10 October 2022 (UTC)

---

I'm also considering splitting the article for genetics of [congenital] red-green color blindness, which could use quite a bit of expansion. Thoughts? Curran919 (talk) 12:13, 3 June 2022 (UTC)

• Is the current article to big to expand this part in place? It's unclear why you want to do a split at this point. And why just red–green? Dicklyon (talk) 21:26, 25 September 2022 (UTC)

  @Dicklyon This split belies an underlying problem with this article, in that it is hard to separate colorblindness as a generic symptom of many conditions from congenital red-green colorblindness, which is by far the most prevalent condition that leads to colorblindness. In other languages, the condition is called Daltonism, which solves a lot of issues, but in English, the lack of a unique sounding name makes the two pretty impossible to separate. Both Achromatopsia and blue cone monochromacy have their own articles to spin off subtopics like each of their genetics, but not "Daltonism", despite being way more common and more deeply studied. Conversely, Congenital Blue-yellow CVD which also lacks its own page is way less common and way less well studied, so I could never see it getting its own article. I also find that the section to split is already much more technical than the rest of this article and that's before going into some necessary (but avoided) aspects of it. The genetics of "Daltonism" are also a widely referenced textbook case for many effects in genetics such as chimerism, X-linkedness, duplication, etc. It's prominence as a topic often completely outside of the "colorblindness as a symptom" topic is another reason to split. Splitting the "Daltonism" and the general symptom would be ideal (then r/g genetics and daltonism could stay together), but I just don't know how I'd do it... Curran919 (talk) 21:49, 25 September 2022 (UTC)

  Sounds good. Why not call it Daltonism then? Dicklyon (talk) 21:56, 25 September 2022 (UTC)

  @Dicklyon because that is not a name in English parlance for almost a century, unfortunately. It's just easier to separate the two when discussing it! "congenital red-green color blindness" is really the only naming option to distinguish from the general symptom, but everyone just conflates the two as "color blindness". If I were to split with the above name, then I reckon "colorblindness" would gradually shift to contain more "daltonism" content and someone less informed would eventually propose and execute a merge. Even with heavy moderation, the two articles would still have a lot of redundancy. It would be a very messy process. Splitting the genetics seemed the cleanest way to make some kind of split in concepts, but I'm very open to ideas. Curran919 (talk) 05:39, 26 September 2022 (UTC)

  I see many dictionaries defining Daltonism as red–green color blindness, but I guess it loses out to that per COMMONNAME. Dicklyon (talk) 17:01, 26 September 2022 (UTC)

  Agreed that there are enough sources and discussion of this particular phenomenon to warrant an independent article. ―Justin (koavf)❤T☮C☺M☯ 22:14, 25 September 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Confusing statement

in the "design implications" section, the sentence "For denotative tasks, using colors that are classically associated with a color name. For example, do not use burgundy (█) to represent "red".", if I understand it correctly seems to say that we should use, use colors associated with a color name, then gives an example saying not to do that.. So which way is it? Dhrm77 (talk) 19:15, 30 October 2022 (UTC)

Thanks, I have clarified the passage. Curran919 (talk) 21:00, 31 October 2022 (UTC)