INTERNAL: Difference between RGB and CMY color models -- triplets

Topic:
Computer screen color models, RGB vs CMYDiscussion:
The CMY (Cyan-Magenta-Yellow) Color Model is a subtractive model, as opposed to the RGB (Red-Green-Blue) Color Model, which is additive.

The terms subtractive and additive refer to the properties of the models with respect to the origin. In the CMY model, the origin (0,0,0) is white and CMY primary colors are subtracted from white to yield a particular color. In the RGB model, the origin (0,0,0) is black and RGB primary colors are added to black to yield a particular color.

Another way to look at the CMY model is to think about what happens, on white paper, if you SUBTRACT all three of the primary colors from white. In other words, if you paint the full intensities of Cyan, Magenta, and Yellow onto the paper (CMY color triplet 255, 255, 255). The result is black. This is the reason that color printers use the CMY Color Model; they paint intensities (densities) of the Cyan, Magenta, and Yellow primaries onto white paper.

The coordinate spaces of the RGB Color Model and the CMY Color Model are the same, except for the fact that the origin (0,0,0) in the CMY model is white, instead of black.

Since white is (255,255,255) in the RGB model, the vector equation to convert from RGB to CMY is:

(C,M,Y) = (255,255,255) - (R,G,B)

For example, if I have a color represented by the RGB triplet (181,97,207), the corresponding CMY triplet would be (74,158,48).

Likewise, since black is (255,255,255) in the CMY model, the vector equation to convert from CMY to RGB is:

(R,G,B) = (255,255,255) - (C,M,Y)
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