Technology · 2026-11-01 · Afternoon briefing

Switchable tattoos offer impermanent body art

Researchers at the University of Colorado Boulder have developed tattoo inks that can be rendered visible or invisible on command. The "PhotoTat" inks, detailed in the journal Matter & Light, appear when exposed to a UV torch and disappear again under white light. The pigments are encapsulated in a medical-grade polymer commonly used in dentures and bone cement.

A commercial version is already available. A red pigment, launched in 2024 by biotech firm Hyprskn as 'Magic Ink', costs £77 for a 2ml vial—around 100 times the price of regular ink. The university team has also created blue, magenta, and yellow inks that can be combined to produce 16 different colours.

The technology's primary test subject has been its lead researcher, Carson Bruns, who says he has hundreds of the tattoos on his own legs. Wider adoption may wait on durability improvements; the current blue ink degrades after just 10-100 activations, leaving behind a permanent purple mark.

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