How can you describe the color gray to a blind person?
You actually truthfully cannot explain a color to a blind person because it will only confuse him than help him. There are organizations that do help the blind with their technology for blind people.
Some people can be blind to specific colors but if you are fully colored blind, it's black, gray, and white i believe. I just see the colours differently. There are no colours I cant see as far as I have been made aware of. My uprising gave me an eye test for it and I have trouble distinguishing certain colours but I can see there is a difference.