I think I have fairly normal color vision, but while digging through the sock drawer, I sometimes have trouble distinguishing black from very dark blue. I also have trouble distinguishing very dark blue from very dark green. But generally no trouble distinguishing very dark green from black. It may have something to do with artificial light. Once I get outside, the differences are clear. Barbara, on the other hand, doesn't have any trouble in artificial light, so I get her to color coordinate my wardrobe. That way, when I go outside, little kids don't point at me and giggle. At least, not about that.

"Red light, officer? What red light?"

Don Firth