By Ray Sparvell
WA researchers have uncovered a long-lost secret of Egyptian mummies which could one day be used to catch out criminals by revealing fingerprints on surfaces that might otherwise escape detection.
Forensic researchers from Curtin University, working with conservation scientists from the Indianapolis Museum of Art, have discovered an Ancient Egyptian pigment that doubles as a fingerprint dusting powder on challenging surfaces.
Luminescent qualities of the pigment reveal fingerprints.Credit: Curtin University
The team found Egyptian blue pigment, used in painted artefacts dating back millennia, also acts as a near-infrared luminescent fingerprint dusting powder that works on highly patterned and reflective surfaces.
Forensic professor Simon Lewis said the detection of latent fingerprints was still a critically important task for forensic investigators.
Secrets of the mummies - pigment used by ancient Egyptians could help police fingerprint criminals.Credit: Curtin University
"The most common approach to detecting latent fingerprints has been the use of dusting powders made from white, black or fluorescent powders that provide contrast against the surface," Professor Lewis said.
"However, there remains many highly patterned and/or reflective surfaces that continue to prove troublesome, making it hard to see fingerprints.
"An alternative approach is to use dusting powders that exhibit near-infrared luminescence, which is invisible to the eye. Such powders can highlight ridge detail while avoiding interference."
Indianapolis Museum of Art researcher Dr Gregory Smith has used special imaging to locate Egyptian blue pigment on ancient artefacts for more than a decade.
"I'd always wanted to investigate Egyptian blue for fingerprint application because it exhibits strong photoluminescence," Dr Smith said.
"It's also non-hazardous and very stable, with painted artefacts dating back several thousand years still showing strong luminescence."
Egyptian blue, also known as cuprorivaite, is the earliest known synthetic pigment. It was first prepared in ancient Egypt before 3200BC and was used extensively until the 4th century AD, when its synthesis was apparently forgotten.
"The secret as to how to make it was lost after the Roman period, but then rediscovered in the 19th century," Dr Smith said.
Professor Lewis said further studies using a wider range of surfaces and fingerprint donors were required to establish the operational usefulness of the powder for forensic investigators.