Friday, 6 September 2013

Unmasking hidden tattoos

It is now possible to reveal tattoos that have been erased or covered up by new tattoos using a combination of spectroscopic techniques. A lot of people get tattoos in a moment of madness which they later regret, so they have laser treatment to remove them. Others are happy to decorate their bodies this way but may feel like a change, so they go for a second tattoo which covers up the first. In both cases it can be difficult, if not impossible, to make out the original design.

Now, scientists from UCL have taken a two-pronged approach to visualising hidden or removed tattoos, described in the Journal of Forensic Sciences, using a tattooed pig's leg and a much-tattooed man as subjects. In the first instance, they used near-IR spectroscopy which was able to reveal some of the original detail, visualisation depending on the wavelength of the light that was used. No single wavelength performed the best of the three that were employed.

The second method was radiography. Using different settings to those used for examining bone, there was some success in making out the presence of tattoos that had been removed or covered up, due to the presence of metallic traces in the original inks.

Victims of mass disasters are often identified from their tattoos. Now, these techniques will help in cases where a body has been dismembered or the outer layer of the skin has been damaged by fire. They will also help in criminal cases where suspects have had known tattoos removed or changed to try and hide their identity or their affiliation with a particular gang.

Friday 6 September 2013


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