UV tattoos or blacklight tattoos are tattoos made with a special ink that is only visible under a blacklight. They are particularly popular in the raver subculture.

The tattoos can be completely invisible in normal light, although scarring from the tattoo machine in the application process may remain, and therefore still show. A UV tattoo becomes visible under blacklight, when it glows in colors ranging from white to purple, depending on the ink chosen. Colored ink is also available, where the ink is visible in normal light (as with a regular tattoo) but the ink will glow vividly under UV light.

Credit:Wikipedia