Criminal minded / Color-blinded / Looking for the red and green / You can’t find it

A few months back at my irregular vision checkup, I learned something that every woman I’ve met has known: I’m color-blind. Not severely, mind you, but enough that I’m unable to distinguish the number in the image to the side.

I believe I’m afflicted by “anomalous trichromacy”, probably “Deuteranomaly”, which, according to Wikipedia, means greens are weak and reds are stronger to my eyes, and affects 6% of men, . While it doesn’t affect me in my everyday life, I found my “deficiency” interesting enough to try operating without the benefit of any color cues.

The easiest way for me to do this was on my computer, where it’s dead-simple to turn off color. I launched System Preferences and opened Universal Access, a preference pane designed to make Mac OS X easier for disabled people to use. You can have your Mac speak the textual interface to you, make the entire screen bigger and reverse colors to white on black.

You can also turn everything grayscale, eliminating all color completely.


I lived without color for weeks (and consistently freaked out people who came into my office), and what I learned is most people have no idea how important color is in communications. Here’s a typical iChat window, but in greyscale.


Can you tell who’s available (green), who’s idle (yellow) and who is away (red)? That’s how many color-blind people see things. Here’s that window again, in color:


Much clearer, isn’t it? (Note, even in color I can’t easily distinguish between green and yellow, and often have to give it a second glance.)

Fortunately, Apple tends to care about the issues of the disabled, and have thoughtfully put options into iChat to use shapes to distinguish state: circles for available, triangles for idle and squares for unavailable.


Not everyone is so considerate. Even Apple’s Server Admin tool uses red and green icons to indicate status. In greyscale, it’s nearly impossible to tell them apart, especially with no legend saying “this is what red looks like”.


You’ll find many transgressors in help manuals, where they’ll ask you to, for example, “click the red button to stop recording”.

(I’ve been keeping an eye open for poorly designed applications that use color as a primary interface, and I’m surprised to say I haven’t encountered too many.)

I suggest living in greyscale for a few weeks to see how the other, uh, 6% lives. For the first few days, it’ll feel weird, and you’ll realize how important color is. After a while, switching back to color will either be a huge relief, or you’ll find the color to be garish and bright. (The latter is what happened to me, and I had to get used to color all over again.)

You might also try software that simulates various color-blindness, such as Sim Daltonism or Color Oracle. It can be an eye-opener.