Better Protected: A cropped image of Wunubi Spring, the first artwork protected by the chemical fingerprint. It was painted by West Australian Aborigine artist Freddie Timms.
Credit: Freddie Timms
SYDNEY: Adding a chemical 'fingerprint' could stop fraudulent paintings being passed off as genuine Aboriginal artworks, say Australian researchers.
The 'fingerprint' – a unique combination of rare or trace elements – can be added to the canvas, frame or paint, and could help museums and insurance companies keep track of valuable Indigenous artworks that are increasingly the target of fraud, the researchers say.
Paint database
Art fraud costs billions of dollars internationally each year. Experts test for forgeries by analysing the chemical signature of paint; the ratio of isotopes of trace elements in the pigment (isotopes are varieties of elements with different numbers of neutrons, for example carbon 12 or 14).
This ratio can then be matched against a database of the chemical composition of paint from particular manufacturers, or in the case of older Indigenous artworks, the geographical region that yielded the ochre used in the painting.
The research was presented this week at the 19th International Symposium on the Forensic Sciences in Melbourne.
The researchers created a database of approximately 4,500 samples of acrylic and oil paints as well as ochre from Indigenous artworks and sites across Australia. The samples were taken using a high-powered laser to vaporise small amounts of pigment and subsequently analysed for their trace element composition.
"The problem is if we are looking at what we think is a forgery we can only identify the manufacturer and batch number [of the paint]," said Rachel Green a forensic scientist at the University of Western Australia in Perth.
Invisible spray
In order to uniquely identify the artist or collective that created the artwork, Green and colleague forensic scientist John Watling, also from the University of Western Australia, have developed an invisible chemical cocktail that can be sprayed onto a painting. The molecular composition of the chemicals – their abundance, type and ratio – creates a unique chemical 'fingerprint'.
The chemicals can be applied before the painting is started, or afterwards, on top of the paint, and don't adversely affect the artwork.
"We invented the chemical encoding to trace [the provenance] back not just to the manufacturer but to the individual artist," said Green.
