New technique to detect fingerprints

On average, only 10% of the fingerprints found at the crime scene are of sufficient quality for investigators to use. A team of scientists are working to increase this ratio by using a polymer film that can change colors.

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The fingerprints are often difficult to detect with the naked eye and therefore are less likely to be perpetrated by the perpetrator. However, the problem is that they are made only by a small amount of sweat or oil on the skin depending on age, exposure to the environment. As a result, fingerprints are often used to mark non-obvious images.

Scientists from the University of Leicester (UK), the Laue-Langevin Institute (France), the ISIS Scientific and Technological Equipment Council have adopted a different approach. This technology is designed to detect hidden fingerprints on metal objects such as guns, knives or cartridges. Instead of using a sticky fingerprint on the rest of the scene, they create a non-stick electrostatic polymer film . The film forms on the metal surface and changes color when there is an electric current running on the surface. Because of insufficient fingerprints, there is a negative image, in which the distance between the lines and the fingerprint of the fingerprint is highlighted.

In addition, the polymer also contains other fluorescent dye molecules when exposed to light or other electromagnetic radiation sources. Therefore, by using electricity and light to create two different colors, forensic investigators can refine the fingerprint image for the most obvious result.

According to a recent study published in the journal Faraday Discussions, a similar study by researchers at the Hebrew University of Israel, Accordingly, traces are taken from the surface of the paper by using gold particles attached to the paper but not on the fingerprint.