Editing RGB color spaces (section)

==Definition==
[[File:RGB Cube Show lowgamma cutout b.png|thumb|300px|RGB cube]]
The normal human eye contains three types of color-sensitive [[cone cell]]s. Each cell is responsive to light of either long, medium, or short wavelengths, which we generally categorize as red, green, and blue. Taken together, the responses of these cone cells are called the [[CIE 1931 color space#Tristimulus values|Tristimulus values]], and the combination of their responses is processed into the psychological effect of color vision.

RGB use in color space definitions employ primaries (and often a white point) based on the RGB color model, to map to real world color. Applying [[Grassmann's laws (color science)|Grassmann's law]] of light additivity, the range of colors that can be produced are those enclosed within the triangle on the chromaticity diagram defined using the primaries as [[Vertex (geometry)|vertices]].<ref>{{cite book|last=Hunt|first=R. W. G|title=The Reproduction of Colour (6th ed.)|year=2004|publisher=Chichester UK: Wiley–IS&T Series in Imaging Science and Technology|isbn=0-470-02425-9|url-access=registration|url=https://archive.org/details/reproductionofco0000hunt}}</ref>

The primary colors are usually mapped to [[xyY]] chromaticity coordinates, though the '''uʹ,vʹ''' coordinates from the UCS chromaticity diagram may be used. Both xyY and uʹ,vʹ are derived from the [[CIE 1931 color space]], a device independent space also known as '''XYZ''' which covers the full [[gamut]] of human-perceptible colors visible to the [[CIE 1931 color space#CIE standard observer|CIE 2° standard observer]].