Researchers come up with a technique to detect wiped off fingerprints

Researchers come up with a technique to detect fingerprints even after you wipe off.




Each human is said to be unique, since their biometric data can never match others. The chances of two having similar fingerprint is very rare even when we test fingerprints obtained from 64 billion people. It helps them retain identity and even provide a proof to gain access to many services. 

The police uses this to identify the culprit without any doubt in many cases. But in crime scenes, the fingerprints which play an important role in getting the police close to the culprit is wiped off many times. This makes police struggle due to lack of evidence to catch hold a criminal. However hand gloves are widely used by professional criminal to make sure that there is no chance of their fingerprints at the crime spot. But in case the criminal has no hand gloves but still is successful in getting rid of his fingerprints making sure there is no evidence that would point to them is a worst case. 

If criminals find a technique to destroy, smart researchers find the way to gain as much information possible from it. Scientists from Leicester University, the ISIS research center in Oxford and the Laue-Langevin Institute in France are said to have come up with a technique to regain the fingerprints no matter how much a criminal tries to wipe it out.

But how do these fingerprints form on any solid we touch?
The human fingers are all time covered with tiny amount of sweat and natural oils. So when it comes in contact with any solid surface, it leaves a pattern formed by the deposition of this sweat and natural oils, exactly similar to that on the finger, helping in identification. But these are barely clear requiring several techniques to enhance. Out of these techniques one makes use of colour powder which could get itself attached to this deposited pattern replicating one's finger pattern giving a enough clear pattern for examination. But this fails to reproduce if wiped off or even aged.

According to sciencedaily, the new technique is very sensitive and will use the combination of electrochromic and fluorescence approach to develop the colour-changing fluorescent films helping in detection of fingerprints on guns, rods, knifes and any other metal surfaces.

Exploiting the electrical characteristics like insulation of the fingerprints, researchers just with very tiny amount about nanometer thickness of sweat pattern are able to develop the fingerprints. Making use of this insulation property which helps them act like a barrier to the electric current used for deposition of coloured electro-active films, a controlled deposition in the region uncovered by the fingerprint pattern is obtained. Thereby using electrochromic polymers that changes color when a voltage is applied. 

This technique is still under development. The recent add on to the conducting film being the fluorophore molecules with suitable conditions, neutron reflectivity measurements employed for achieving required distribution and avoiding its reach to the bottom metal surface. This fluorophore emits light when exposed to any kind of electromagnetic radiation(example light), thereby developing a combination of electrochromic and fluoroscence effects giving them freedom to control the emission colour to generate a sharp contrast by just adjusting voltage and the amount of radiation incident on it.

Soon this technique after testing with surface with fingerprints exposed to different conditions, will come into action in real world helping reproduce fingerprints even after attempts to wipe it.

Comments