My husband is colour blind and can't see the difference between colours at the same saturation level. He's a real asset to my quilt making as he sees pattern and shades before colour. I often ask him if things go together and he's able to tell me that there isn't enough contrast or too much. When he was in ROTC, he was recruited as a sniper because of his keen ability to see shapes. When we hike in the woods, he will point out a bird or animal while I'm trying to look through the leaves and not seeing it. Before meeting him, I felt sympathy for people who were colour blind, but now I see tons of benefits. NOT that I would give up my colour vision in exchange. As they say, opposites attract and it so happens I have a hyper-sensitivity to colour. I always get 100% on those tests to match colours and if there is a disharmonious bit of colour in a scene, my eye will jump to it and I have to consciously look at other places. I would love to get my husband a pair of those glasses to see colour but the cost is prohibitive. Then he could wear them and refer correctly to items. I'm always careful to not refer to something as "the green towel" but provide a different description. He doesn't think of that, so says things like "I like that blue shirt" while looking at something purple. For years he called his survival suit his "yellow suit" but it's fluorescent orange. Sometimes I correct him, usually not.