Living in Grayscale
There are a variety of color blindness testers, but a new one from A List Apart is Nocturne, a free Mac app which allows you to quickly disable color on your monitors, add tints or even invert the colors of your monitor.
In fact, I'm writing this blog entry in grayscale mode right now. Cool!.
In terms of accesibility, gray scale is recommended as a way to sense how well a Website will perform in terms of contrast and color blindness, which also relies on contrast. While it's good to see how your Websites check out (most are usable) and how Madonna looks in black and white (awesome of course), I found the real challenge was in doing something fast...like playing a video game.
So, I experimented with playing a version of Bejeweled in black and white because you have to rely on color so much. Result: Total nightmare!. Although I'm able to decipher static icons and menus and enjoy Youtube videos, the result for the game was a major meltdown. It moves very fast, and some of the shapes are quite similar - it was really hard to distinguish the spherical jewels from the hexagonal jewels and the octagonal jewels. The hue really is the major cue here.
Inverted mode was also interesting. The play was easier, but a some of the colors inverted to similar shades of blue. This is similar to the problem most color deficient viewers have - they can see colors, but not all of them. Colors which contrast vividly for us, particularly red/green, are just similar shades of yellow or brown for this audience.
So for me, the main lesson is that color deficiency is not a huge challenge (obviously), but there can be an impact in speed if shapes are not distinct enough. Fortunately, I think most color deficient folks have had a lot of practice compensating.