FORENSIC researchers from Curtin University, in conjunction with conservation scientists from the Indianapolis Museum of Arthave found a novel use for an ancient Egyptian pigment, revealing that it doubles as a dusting powder able to reveal traditionally tricky fingerprints in modern forensics.
The team demonstrated that micronised Egyptian blue pigment, a vivid and long-lasting pigment used in painted artefacts dating back millennia, also acts as a near-infrared (NIR) luminescent fingerprint dusting powder, providing a safe and simple way to reveal latent fingerprints on highly patterned and reflective surfaces.
Professor of Forensic and Analytical Chemistry and member of the Nanochemistry Research Institute at Curtin’s Department of Chemistry Simon Lewis said the detection of latent fingerprints was still a critically important task for forensic investigators, helping to establish evidence of contact between the criminal, the victim and/or the crime scene.
“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,” he said.
“However, there remain 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.”
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 fourth century, when its synthesis was apparently forgotten.
Researchers compared commercially available fingerprint powders and micronised Egyptian blue pigment for their ability to reveal fingerprints on a range of surfaces.
They then used an inexpensive white light source to illuminate the prints and a slightly modified, consumer digital camera to photograph them.
The prints dusted with Egyptian blue glowed brightly in the NIR under the white light, consistently outperforming the commercial powders on patterned and reflective surfaces.