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. However, some UV inks are not as bright under normal light as normal tattoo ink and are considered not as vibrant.
Maybe those UV are also extreme tattoos and also bizarre and weird tattoos. UV tattoo ink is not commonly known or used, as very few varieties of UV inks are approved for use in the US. It is also many times more expensive than regular tattoo inks. Some people have had reactions to ingredients in the ink, ranging from minor itching to dermatitis. Several UV inks are suspected carcinogens and allergens and at this time, no research has been conducted into the possible side effects of long term exposure. Some UV inks are known to yellow or turn slightly brown with sun exposure.