https://www.live-feeds.com/feed/cool-chemistry-trick-allows-new-tattoos-to-turn-on-and-offContinuously updated, source-cited coverage. https://www.live-feeds.com/feed/cool-chemistry-trick-allows-new-tattoos-to-turn-on-and-offhttps://www.live-feeds.com/feed/cool-chemistry-trick-allows-new-tattoos-to-turn-on-and-off#u122595Thu, 15 Oct 2026 01:33:46 +0000Scientists have developed tattoo inks that can be activated by different wavelengths of light, allowing people to hide or display their tattoos. The inks can be switched on with ultraviolet light and made to disappear in sunlight. This technology uses photochromic pigments encapsulated in PMMA, which can last for up to 2.2 years in skin.Why it mattersThis innovation has potential medical applications and could change how people view tattoos. The ability to control tattoo visibility could be useful in various scenarios. Researchers have been experimenting with tattoo inks that can change appear