New infra-red camera can get under the tattooed suspect's skin

Published on Sunday 13 December 2009 21:52

A NEW infra-red camera could help solve crimes by identifying hidden tattoos.

Forensic scientists and detectives already look at tattoos as a way of identifying suspects or finding leads in investigations, but criminals can easily have them changed or updated.

Scientists say using an infra-red digital camera could help determine if a tattoo is an original or a new tattoo covering the old one.

A traditional colour camera only picks up what is on the surface of the skin.

But using a digital camera sensitive to infra-red, researchers can see if there are hidden layers or changes to the original tattoo deeper in the skin.

In a recent experiment, the technique found that on a student's back a butterfly image had covered up an image of an imp in the original tattoo.

David Bryson, senior lecturer of applied photography and forensic science at the University of Derby, said: "Identifying individuals using tattoos has been an established part of forensic science practice for some time, but there can be cover-ups of tattoos with lasers, more tattoos or surgery.

"It is now possible to take a control photograph and a separate photograph with an infra-red filter to take images of the tattoo, and determine if it is indeed the original or is a cover-up, or altered tattoo on the surface.

"Digital photography means that moments after the images have been taken, they can be viewed on a computer screen – making this interesting approach now more feasible for use in everyday forensic work, compared to more traditional processes."

More research at the university's labs is also looking at the criteria that lead to the underlying tattoo being visible to infra-red or not visible to infra-red.