This is a very stupid picture. It only says something about the poor, inaccurate desaturation algorithm used and nothing about optical effects. --90.156.104.160 (talk) 12:47, 28 February 2017 (UTC)
The claimed property is not even remotely true. This is what ImageMagick -colorspace GRAY outputs: http://snow.haasn.xyz/~nand/gray.png and this is what -colorspace XYZ -separate outputs for the Y channel: http://snow.haasn.xyz/~nand/xyz-1.png 109.193.81.112 (talk) 22:03, 23 June 2017 (UTC)
