I’ve been playing with a blacklight here at Debconf, during the keysigning party. (Hey, I’m a geek; what did you expect.) Of course, I cannot resist sharing what I saw:

• US passports are very dull under the blacklight. From the older ones that don’t reflect anything, to the newest ones that feature a security thread in three colours and UV-sensitive fibers embedded in the pages and the inner covers, they are not exactly a party of lights and colours.
• However, they are not the dullest. That “honour” goes to Brazilian passports, which contain no UV markings whatsoever. Runners-up are British passports, with only some crown markings in the inner covers.
• Belgian passports blew me away, with a colour photograph which only appears under the blacklight. Luxembourgish passports are similar, but have no photo.
• Talking about photos, one passport Greek passports contain the person’s photo in UV-sensitive ink. However, I don’t remember what country it was (please add a comment).
• Greek and Spanish passports light up with patterns when you illuminate them. Colombian and Mexican passports do, too.
• Austrian passports have “Republik Österreich” written in UV-sensitive light in their cover. Spanish passports have the Spanish coat of arms and the word “España” over and over.
• Swiss passports don’t need any UV markings, because they are already full of colours in plain light.

I looked at more passports, but those are the ones I can remember off the top of my head.

A couple of notes before I publish this post:

• I would have liked to look at a Japanese passport.
• If you’d like to look at your own passport under a UV light, I’m at the top floor hacklab :)