University of Colorado Boulder researchers develop light-activated tattoos

Researchers at the University of Colorado Boulder have developed a new type of photochromic ink called ‘PhotoTat’ that allows tattoos to appear or disappear depending on light exposure. The technology uses tiny spheres of polymethyl methacrylate (PMMA), a material commonly used in medical applications like dermal fillers, to house specialized dyes.

Under normal conditions, the ink remains invisible to the human eye. However, when exposed to ultraviolet (UV) light, the molecular structure of the dyes changes, causing them to absorb different wavelengths and reveal colors. By combining primary pigments such as magenta, cyan, and yellow within these spheres, researchers can create full-color images.

Initial experiments on artificial skin demonstrated that ten seconds of sunlight can activate the tattoo for several hours, while exposure to LED light can cause the image to fade almost instantly. Lead researcher Professor Carson Bruns noted that this technology could allow individuals to hide body art for professional settings or personal preference.