List of color spaces and their uses

Wikimedia list article

This is a list of color spaces and their uses.

Contents

ModelsEdit

There are five major models, that sub-divide into others, which are: CIE, RGB, YUV, HSL/HSV, and CMYK.

 
Additive color mixing
 
Subtractive color mixing

CIEEdit

CIE 1931 XYZEdit

Main article: CIE 1931 color space

(aka "CIE 1931") The first attempt to produce a color space based on measurements of human color perception and it is the basis for almost all other color spaces.

CIELUVEdit

Main article: CIELUV

A modification of "CIE 1931 XYZ" to display color differences more conveniently. The CIELUV space is especially useful for additive mixtures of lights, due to its linear addition properties.[1]

CIELABEdit

Main article: Lab color space

The intention of CIELAB (or L*a*b* or Lab) is to produce a color space that is more perceptually linear than other color spaces. Perceptually linear means that a change of the same amount in a color value should produce a change of about the same visual importance. CIELAB has almost entirely replaced an alternative related Lab color space "Hunter Lab". This space is commonly used for surface colors, but not for mixtures of (transmitted) light.[1]

CIEUVWEdit

Main article: CIE 1964 color space

Measurements over a larger field of view than the "CIE 1931 XYZ" color space which produces slightly different results.

RGBEdit

RGBEdit

RGB (Red, Green, Blue) describes what kind of light needs to be emitted to produce a given color. Light is added together to create form from darkness. RGB stores individual values for red, green and blue. RGB is not a color space, it is a color model. There are many different RGB color spaces derived from this color model, some of which appear below.

RGBA is RGB with an additional channel, alpha, to indicate transparency.

sRGBEdit

Main article: sRGB color space

The sRGB color space, or standard RGB (Red Green Blue), is an RGB color space created cooperatively by Hewlett-Packard and Microsoft Corporation for use on the Internet. It has been endorsed by the W3C, Exif, Intel, Pantone, Corel, and many other industry players. It is also well accepted by Open Source software such as the GIMP, and is used in proprietary and open graphics file formats such as SVG.

sRGB is intended as a common color space for the creation of images for viewing on the Internet and World Wide Web (WWW), the resultant color space chosen using a gamma of 2.2, the average response to linear voltage levels of CRT displays at that time.

Adobe RGBEdit

Main article: Adobe RGB color space

The Adobe RGB color space is an RGB color space developed by Adobe Systems in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as the computer display. The Adobe RGB color space encompasses roughly 50% of the visible colors specified by the Lab color space, improving upon the gamut of the sRGB color space primarily in cyan-greens.

Adobe Wide Gamut RGBEdit

The Adobe Wide Gamut RGB color space is an RGB color space developed by Adobe Systems as an alternative to the standard sRGB color space. It is able to store a wider range of color values than sRGB. The Wide Gamut color space is an expanded version of the Adobe RGB color space, developed in 1998. As a comparison, the Adobe Wide Gamut RGB color space encompasses 77.6% of the visible colors specified by the Lab color space, whilst the standard Adobe RGB color space covers just 50.6%.

One of the downsides to this color space is that approximately 8% of the colors representable are imaginary colors that do not exist and are not representable in any medium.[2] This means that potential color accuracy is wasted by reserving these unnecessary colors.

Other RGB spacesEdit

There is an open ended set of RGB spaces; by picking new red, green, blue primaries and a gamma value, anyone can invent one. The following have articles:

Luma plus chroma/chrominanceEdit

YIQ, YUV, YDbDrEdit

Main articles: YIQ, YUV, and YDbDr

YIQ was formerly used in NTSC (North America, Japan and elsewhere) television broadcasts for historical reasons. This system stores a luma value with two chroma or chrominance values, corresponding approximately to the amounts of blue and red in the color. It corresponds closely to the YUV scheme used in PAL (Australia, Europe, except France, which uses SECAM) television except that the YIQ color space is rotated 33° with respect to the YUV color space. The YDbDr scheme used by SECAM television is rotated in another way. (work needed)

YPbPr, YCbCr, ICtCpEdit

Main articles: YPbPr, YCbCr, and ICtCp

YPbPr is a scaled version of YUV. It is most commonly seen in its digital form, YCbCr, used widely in video and image compression schemes such as MPEG and JPEG. ICtCp is the optimized high dynamic range version of YCbCr.

xvYCCEdit

Main article: xvYCC

xvYCC is an extension of YCbCr that extends the color gamut beyond the R/G/B primaries specified by BT.709.

Cylindrical transformationsEdit

HSV and HSLEdit

Main article: HSL and HSV

HSV and HSL are transformations of an Cartesian RGB colorspace (usually sRGB), and their components and colorimetry are relative to the RGB colorspace from which they are derived. HSV (hue, saturation, value), also known as HSB (hue, saturation, brightness), is often used by artists because it is often more natural to think about a color in terms of hue and saturation than in terms of additive or subtractive color components. HSL (hue, saturation, lightness/luminance), also known as HSI (hue, saturation, intensity) or HSD (hue, saturation, darkness), is quite similar to HSV, with "lightness" replacing "brightness". The difference is that a perfectly light color in HSL is pure white; but a perfectly bright color in HSV is analogous to shining a white light on a colored object. I.e. shining a bright white light on a red object causes the object to still appear red, just brighter and more intense. Shining a dim light on a red object causes the object to appear dark and less bright.

CIELChab and CIELChuvEdit

CIELChab and CIELChuv are cylindrical transformations of the CIELAB and CIELUV color spaces, respectively. The cylindrical coordinates C* (chroma, relative saturation) and h° (hue angle, angle of the hue in the color wheel) are specified. The CIELAB and CIELUV coordinate L* (lightness) remains unchanged.

CMYKEdit

CMYKEdit

Main article: CMYK color space

CMYK is used in the printing process, because it describes what kind of inks need to be applied so the light reflected from the substrate and through the inks produces a given color. One starts with a white substrate (canvas, page, etc.), and uses ink to subtract color from white to create an image. CMYK stores ink values for cyan, magenta, yellow and black. There are many CMYK colorspaces for different sets of inks, substrates, and press characteristics (which change the dot gain or transfer function for each ink and thus change the appearance).

Commercial color spacesEdit

Special-purpose color spacesEdit

  • The rg chromaticity space is used in computer vision applications, and shows the color of light (red, yellow, green, etc.), but not its intensity (dark, bright).
  • LMS color space (long, medium, short), a perceptual color space based on the response functions of the cones in the retina of the eye. It is mostly used in psychophysical research.

Obsolete color spacesEdit

Early color spaces had two components. They largely ignored blue light because the added complexity of a three-component process provided only a marginal increase in fidelity when compared to the jump from monochrome to two-component color.

ReferencesEdit

  1. ^ a b Keith McLaren; "Dyes, General Survey" in: Ullmann's Encyclopedia of Industrial Chemistry; Wiley-VCH; 15 June 2000.
  2. ^ [1]

External linksEdit