I think that this article drastically over-complicates color. Color can be defined in two separate and distinct ways.

First, color is light in varying wavelengths and intensities.

Second, color is a perception in the mind of a creature with light receptors.

A tree falling in a forest without an observer is not black and white, because the lack of an observer does not change the wavelengths of light absorbed by the tree. The perception of color, however is dependent on the receiver. A creature with dichromatic vision has a different perception of colors than a trichomat or a tetrachromat.

This article makes color sound very confusing by not setting a clear scope at the beginning. The resulting ambiguity is the source of "philosophical discussion".