>One of my managers at the Health Dept. was profoundly colorblind. Our best test for the design of a screen/form was to have him sit down at it and tell us what he could see.
>
>Once we figured out the color scheme he could see clearly, and that didn't make everyone else sick, we used it for every other app we created.

When VGA came after the EGA, a colleague pointed out that he doesn't see the need to have five colors. I asked how did he arrive at five, which isn't divisible by two, four, eight etc. "I can distinguish only as many...".