It's interesting to note that many 'experts' on color fail to define what color really is. Could it be that they don't know?
"Newton himself, who actually introduced the word “spectrum” into the English language to refer to the range of possible colors, eventually dismissed the idea that colors are literally contained in the light. “For the Rays, to speak properly, are not coloured. In them there is nothing else than a certain Power and Disposition to stir up a Sensation of this or that Colour.” Three hundred years on, what and where colors actually are remains a mystery."
If you're ready for some mind boggling ideas about color, here are more thoughts on the subject, by Riccardo Manzotti, philosopher, psychologist, and artificial intelligence scholar.