A Tattoo You Can Switch On and Off With Light Is Being Tested
Its inventor has hundreds of test tattoos on his own leg, and they still switch after two or three years.
Global News Podcast · Trump calls for Zelensky to be replacedThe tattoo could be invisible at work and visible at dinner. Carson Bruyns, a researcher working at Colorado Boulder, developed the ink with his team to work like a switch controlled by light.
To turn it on, you shine ultraviolet light on the skin. A normal indoor bulb will not do it. He uses a small light he keeps on his keychain. Bruyns says: "It's only a couple of inches long, and that's enough to turn it on within two, three seconds."
Once on, it stays on. Under normal indoor lighting, the design remains visible for hours or even days. You do not need to keep shining the light to keep it there.
To turn it off, you use the opposite trick, a very bright white light. Hold a cell phone flashlight close to the skin and the tattoo disappears within seconds. It then stays off until you wake it again with ultraviolet. Bruyns describes it this way: "The one light turns it on, then it stays on. The other light turns it off, and it stays off."
Bruyns is so far the only test subject. He has hundreds of these small tattoos on his leg, and he says he can still switch them on and off repeatedly after two or three years. He says that continued switching is an indication that the tattoo really is permanent.
Only one color, sold as Magic Ink, has passed the full battery of sterility, toxicity, and clinical testing needed before inks reach tattoo shops. The other colors have not yet been through that process.
Questions people ask
Is this the same as the black-light tattoos I have seen at clubs?
No. Standard black-light tattoos use fluorescent ink that is faint in normal light and glows only while ultraviolet is shining on it. This ink has a memory. After a few seconds of ultraviolet, it stays visible for hours or days indoors, until a bright white light switches it off.
Is switching it on and off safe for skin?
Switching on takes a special ultraviolet light (a keychain-sized one) for two or three seconds. Switching off takes a bright white light like a phone flashlight held close to the skin for a few seconds. Only the Magic Ink color has completed sterility, toxicity, and clinical testing, while the other colors have not.
When could I get one in more colors?
Not yet, except for the one tested color sold as Magic Ink. Bruyns says the other colors still need to go through the full battery of sterility, toxicity, and clinical testing. No public timeline has been given for when shops might carry them.