Signs for the colorblind

I'm putting this out now even though the cool illustration of the concept has not worked out to my satisfaction.

Color blindness is a condition that a bit over 1% of the population possesses, something like ten times more prevalent among males as compared to females. Here is a typical colored dot test for one of the most common types of color blindness:

If you see the number 21 instead of 74, you probably have red-green color blindness.

The issue is one that web designers need to be concerned with as they put together websites. Here is a tool that lets you visualize what a given website looks like under the different types of color blindness - you can try typing in the URL of this page to see what happens. It would be cool if they could build this into a head-mounted display so a person could go out into the world and experience what it is like to see things with altered color perception.

My idea is to use this phenomenon to make signs that display different messages to different people. For instance, suppose a couple is made up of a normal vision wife and a red-green color blind husband. We could make a design for the bathroom floor out of appropriately tiles that would show the word UP to those with normal vision and DOWN for the color blind viewer, as an aid to behavior modification. My discovery last night is that even though it isn't terribly hard to make words when you're working with just two colors of tile, one needs a hell of a lot of tiles - hundreds, preferably - to display even a short word in a random color pattern in this way legibly, and as tiresome this would be to depict in a drawing program on the computer, it would be even more of a chore to do in actual colored tiles. (Even if the tile-setter isn't color blind.) Perhaps it would be better just to reproduce a pattern in miniature, as a wall hanging instead.

Another idea would be to make little tags which you would sew into your clothing, identifying which tops and bottoms go together when viewed by someone of the majority group - the color blind person would just have to match A with A and B with B instead of relying on their own distinctive color sense.

I think there are probably other applications if one just thinks about the subject for a bit more. I look forward to the comments.

Update (June 2008): In this post I have tracked down a source for those original color plates, if anyone is interested in owning a second-hand set.

Update (December 2010): This T-shirt incorporates some of what I had in mind, although the non-textual part of the design kind of makes it less cool than the full-blown concept, along with a bit of a bad attitude.