Right on. Color description is the most challenging to describe; a person who is colorblind will sill struggle with understanding the description of hues that they cannot see the same way as someone with normal color vision. They can see the same light, but because they have only two (or mostly two plus very few of the third cone) types of color sensitive receptors, they’re composing an image that cannot fill in the other colors, for lack of detection of qualitative information. Right now if I look at my messy kitchen island, I can see blues,greens. Reds pink, some purple, orange, browns and yellow on the various packages. If I use an app that simulates protan or deuteran colorblindness, the same view is reduced to blues yellows and browns. Everything that was red now looks brown. Green things look brown. Basically everything that isn’t blue seems to reduce to browns and yellows.

I have normal color vision, with the usual three types of color receptors. There are a few people who are tetrachromats, and have an additional channel of color information to add to the mix. They still see within the visible light spectrum, but can distinguish colors more easily than I can. This fascinates me, because I’m convinced that I’m seeing everything. But that’s no different from a color blind person making due with two instead of three types of receptor. Intellectually, I understand that four distinct qualitative receptors will report more color information to the brain than three will, but it’s still a challenge. I think of the tetrachromats as seeing what see, but with a much more refined ability to distinguish between very similar colors.