I once had a client whose husband was color blind. We repainted the walls in their house a soft green that he could only see as gray.
Something unexpected happened when the color-blind husband walked in the door. He said that although he could not see the new color, he could feel the difference in the house. It felt like it had let out a big exhale. I believed at that very moment I had confirmed what I had known all along, that color has a lot more to say than meets the eye.