Hmmm, I may be. (I'm not sure how you find out.) I see color with a *LOT* more accuracy than just about anyone I know. I have returned many pairs of shoes, a couple of handbags, and some clothing because I could see that the materials did not match. The sales people usually look at me like I am mentally ill.

I am a gemologist and I'm not sure if that training led me to see color this way or if seeing color this way led me to become a gemologist - probably a little of both. Interestingly, color blind people are the best at color grading diamonds - something that I've never really gotten comfortable with (despite teaching it for a few years!).

Having a very accurate eye for color (whether tetrachromatic or not) is sort of a pain in the backside. Variations that other people don't see are glaringly obvious to me and it can be annoying on both sides. In fixing a big scrape on my car, it wasn't until the fourth attempt that the paint was matched well enough that I didn't feel like I was driving something pieced together from the junkyard. If there is any benefit at all, it's that people think I'm always well turned out - they just have no idea what goes into making that happen!

I browsed the article that left brain mentioned and I've read that it can't be possible using our standard monitors but I found this comment from a random visitor:
"To those mentioning that there would be no tetrachromat test available on a standard three-color monitor - I believe that /human/ tetrachromats would be able to be tested with three color monitors - I recall from somewhere long ago (Mr. Wizard when I was a kid, I think) that normal/trichromat's cannot distinguish between two sequentially numbered Pantone colors, the closest we can usually tell is something like 7 (in daylight) and, assuming our monitors can produce on the order of 16million colors+, then couldn't a tetrachromat test be established with very closely related shades of color? Those that can tell the difference are more likely to be tetrachromats and those that think it's the same color are trichromats?

P.S. I agree that for a tetrachromat with super-visual color perception (i.e. outside of our normal 400-700nm range) we couldn't use a three-color monitor, but I think that's limited to birds, bees, and the like =)."

...so i think it's possible but i haven't found the test yet.

@msgotrox: cool job! ;)

Hello, I know it is much after the fact here - but I am a diagnosed Tetrachromat.  see my site www.TetrachromatArtist.com.