On the one hand you have light waves that hit some receptors in the eye. These receptors (various kinds) sensitive to frequencies according to a function. This creates a specific signal that is analyzed by the brain which assigns a "color" to that signal.
Everyone's, to some extent, functions are different. There is a general trend so most people agree on "colors". When you are colorblind, the functions differ drastically (or are just flat).
This is why "color" is a biological concept (same as, say, "pain") to which we are desperately trying to attach three or four numbers (or, worse, a wavelength)
On the one hand you have light waves that hit some receptors in the eye. These receptors (various kinds) sensitive to frequencies according to a function. This creates a specific signal that is analyzed by the brain which assigns a "color" to that signal.
Everyone's, to some extent, functions are different. There is a general trend so most people agree on "colors". When you are colorblind, the functions differ drastically (or are just flat).
This is why "color" is a biological concept (same as, say, "pain") to which we are desperately trying to attach three or four numbers (or, worse, a wavelength)