Here is a very interesting article on how different cultures divide the colors in the world. What is especially interesting to me is how recently developed cultures like the Japanese divided up blue from green. (Hint: It wasn't that long ago.)
DF is working on colors. He knows that we talk about red and green when it comes to stoplights but he doesn't always get them right. He also knows that one of our cars is the 'black car' but again, I don't know that he has the color actually figured out.