Subtractive Color
Mixing
nDifferent pigments absorb different wavelengths of light
nWavelengths reflected off an object are its “color”
nMore colors more frequencies -- less light
nPrimaries: Blue, Red, and Yellow (actually Cyan, Magenta, Yellow, for best results…)
nCYMK: for printing a black (K) also used
–Better quality black than mixing CYM
–Cheaper
Additively, the more you picture gets white,

Subtractively: more your pictures gets black (or in real life usually a horrible muddy green color…)

If you truly only use three colors –as in process printing, cmy are best. For painters, rgb works because you usually have tubes of many colors, not all of which are mixture of rby at all…