PhotoTat: New Ink Allows Tattoos to Be Hidden or Changed with Light
Researchers at the University of Colorado Boulder have developed PhotoTat, a tattoo ink that can be switched on or off using light. The system uses photochromic dyes in medical-grade plastic nanoparticles, allowing colors to appear under UV light and disappear under bright sunlight. Published in the journal Matter & Light, the technology could enable temporary medical markings or customizable body art without permanent removal.