color has two meanings:
1. the spectrum of light (let's call it real color).
2. the perception of human (let's call it perceived color).
what is the perception of light with certain spectrum? That is
basically a question of decomposition of the spectrum along the 3
axeses of the absorption spectrum of 3 types of molecules in
human retina. Obiously many different spectra can produce the same
perception. Using pure red/green/blue light, we can pretty closely
reproduce all possible color perceptio
