Tattoos leave crucial hints in criminal investigations, and now scientists have discovered a new infrared technique which is capable of identifying hidden tattoos.
The research team from University of Derby suggests that using an infrared digital camera could help determine if a tattoo is an original or a new tattoo covering the old one.
The conventional colour camera only picks up what is on the surface of the skin but digital camera sensitive to infrared can locate hidden layers or changes to the original tattoo deeper in the skin.
Recent experiments showed that on a student's back a butterfly image had covered up an image of an imp in the original tattoo.
"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," the Scotsman quoted David Bryson, senior lecturer of applied photography and forensic science at the University of Derby as saying.
"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," Bryson added.