Looking up Lab* color could be a good start, if you're unfamiliar- color being naturally three dimensional (eg RxGxB), LAB is a projection of color where L attempts to account for every color of a perceived lightness, and A and B account for another two dimensions (green-to-red and blue-to-yellow... you can read the wp page as well as I can). The goal being that a given distance in any direction anywhere in the volume have an equal perceptual difference to the eye, an aspect sorely missing from RGB (where eg 8bits/channel is overkill in some colors but can result in banding in others, as well as being cumbersome to process in, as GP mentioned)

https://en.wikipedia.org/wiki/CIELAB_color_space https://en.wikipedia.org/wiki/Colour_banding