Researchers report multicolored tattoo inks that can be turned “on” or “off” by shining different types of light on the skin. In a study published in *Matter & Light*, the team describes inks that respond to separate wavelengths, allowing a user to selectively change tattoo visibility. The concept is presented as a potential way to conceal tattoos during situations such as work meetings, and the researchers also suggest users could create temporary markings using a simple laser pointer.
Across the reports, the core focus is on the same chemistry-based approach: different colors and light triggers are designed to provide controllable, scenario-dependent visibility. However, both outlets note that key questions remain. In particular, safety and practicality for real-world skin use are not yet proven, including how the inks behave over time and whether repeated light exposure or skin contact poses risks. Further testing is framed as necessary before any potential consumer or clinical use.
