Recovering Fingerprints from Fabrics

Forensic experts at the University of Abertay Dundee and the Scottish Police Services Authority are using a technique known as vacuum metal deposition (VMD) that uses gold and zinc to recover fingerprints from fabrics.

VMD is a highly sensitive technique already used to detect fingerprint marks on smooth surfaces, such as carrier bags, plastics and glass.

The current research study is exploring its use with clothing and the potential value it could bring to a police investigation.

"The research uses fine layers of metals to display fingerprints people may have left on fabrics, something which is far harder to do with soft surfaces, said Joanna Fraser, a forensic sciences researcher at the University of Abertay Dundee. "The technique has been around since the 1970s and is used on many surface but was never widely used on fabrics.

"We take these fabrics, place them in a vacuum chamber, then heat up gold to evaporate it and spread a fine film over the fabric. We then heat up zinc, which attaches to the gold where there are no fingerprint residues. This helps reveal the fingerprint, where contact has been made we see the original fabric, where there was no contact we're left with the grey color of the metal film.

The method works but the researchers must develop it further to confirm its effectiveness. The results indicate fabrics with a high thread count are best for revealing a print, and the researchers have recovered identifiable fingerprints on a number of fabrics including silk, nylon and polyester.