13 Jul 2016
Scientists trial fingerprint development method for Britain’s new polymer banknotes
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New research into the most effective way of lifting fingerprints from polymer banknotes has been led by scientists at Loughborough University.
In September 2016, the Bank of England will introduce a new £5 polymer banknote into circulation. The following year, the same thin and flexible plastic material will be used for a new £10 note, and by 2020, new £20 notes will also be made available.
Developing fingerprints from this new surface represents an important forensic challenge as current imaging protocols for paper currency will potentially become redundant once the new notes are issued.
This preliminary investigation into the recovery of fingerprints from precursor test notes has successfully demonstrated that fresh latent fingerprints, not immediately visible to the naked eye, can be developed using elemental copper deposited via a highly sensitive technique known as vacuum metal deposition (VMD). The results can then be imaged using near-infrared illumination. In addition, a forensic gelatine sheet can be used to lift from the treated note’s surface and then the fingerprints revealed to the naked eye by spraying the sheet with rubeanic acid – a development reagent – which reacts with the copper to produce a visually distinguishable fingermark.
Loughborough University’s Dr Paul Kelly, Reader in Inorganic Chemistry, and his research team from the Chemistry Department, collaborated on the study with forensic science equipment suppliers Foster + Freeman Ltd (led by former Loughborough PhD student Dr Roberto King who worked under Dr Kelly) and the Home Office Centre for Applied Science and Technology (CAST).
Dr Kelly’s approach means that VMD treated polymer notes may potentially be able to re-enter into circulation rather than having to be destroyed. The gelatine lifting procedure provides a physical record of the development process and marks a further advancement of previous gel applications by Dr Kelly and his research group including combating heritage crime (in the form of metal theft) and the extraction of a chemical blueprint from stone – an early trial of a technique to help address the rising issue of stone theft.
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