NCJ Number
219250
Journal
Journal of Forensic Sciences Volume: 52 Issue: 4 Dated: July 2007 Pages: 851-859
Date Published
July 2007
Length
9 pages
Annotation
This research developed a scientific authentication protocol that facilitates the definitive and accurate determination of the source of Australian ocher used in indigenous art, which involves large monetary transactions between art galleries/centers and purchasers.
Abstract
Ochers that come from different regions in Australia have unique trace metal signatures. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used for elemental differentiation and the consequent establishment of the source of ocher samples used in Australian indigenous artwork. Only a single sample of ocher from a specific site is required to obtain accurate and representative trace elemental concentrations for ocher from a particular site. It follows that a single fragment of ocher sampled from an original art piece is sufficiently homogenous for data obtained from its analysis to be used in establishing geographical origin. The artwork samples could be traced back to ocher samples of the same mineralogy and geological origin. A database of ocher has been started, although more samples from more regions of Australia are required before it can have practical use. As the database becomes larger, it can be used to trace ocher back to their geographical origins within Australia, so artworks can be linked with a particular artist. Further study is required to investigate and confirm the nature of the organic constituents of the ocher paints, pigments, fixatives, and artists' specific additives. Thirty-six samples of ocher collected from across northern Western Australia and the Northern Territory were mounted on Blutac on Perspex disks and analyzed using LA-ICP-MS. Each subsample was analyzed for 54 elements. Twenty-six pinhead-sized samples of ocher obtained from 11 different artworks were analyzed in the same manner.