Originally Posted by Etoile

UV ink tattoos are really cool - you can see a gallery of them here: UV and Glow tattoos [BMEink.com Tattoo Gallery]
A good example of how they look after they're healed:
Regular - http://www.bmeink.com/A70727/high/bmepb573818.jpg
Black light - http://www.bmeink.com/A70727/high/bmepb573816.jpg

Here's an example of white ink on white skin: http://www.bmeink.com/A70226/high/bmepb467382.jpg
(It looks much different on dark skin, of course.)

I think both of these are good options for interpreters. I'm considering getting one a few inches below my elbow (on the inside forearm) which will be hidden under long sleeves and mostly invisible under short sleeves, so it should be okay either way.