This is from a black light photoshoot. The model was painted with UV light sensitive paint by a makeup artist and body painter, and then she was illuminated by a black light lightbulb held close by the makeup artist. Originally I had made a DIY UV filter for my flash that was supposed to simulate the light from a black light, so I didn't have to shoot at such high ISO, but it didn't work at all. Luckily I didn't have to push the ISO too high to use the black light light bulb though.

Pentax K-1, 100/2.8 macro @ 1/50, f/2.8, ISO 1250