Speaker Thurs July 10th - Rachel Popelka-Filcoff: Using spectroscopy to view Aboriginal Australian Pigments

Natural mineral pigments are significant in Aboriginal Australian culture, and applied to a variety of natural matrices such as wood and bark to create objects such as boomerangs and shields and bark paintings.  Ochre (Fe-oxide pigment), is used for a variety of red, brown, orange and yellow colours and other natural mineral pigments such as kaolinite are used for white colours. Mixtures and applications of pigments present a challenging analytical problem, especially towards the non-destructive elemental analysis of mixed pigments on objects with a variety of shapes and sizes.

This presentation will describe our recent research into methods to characterize the complexity of Indigenous Australian ochre pigments.  We have studied ochre from several known ochre sources around Australia by several techniques, including neutron activation analysis (NAA), X-ray fluorescence microscopy and near-IR spectroscopy.  The combination of these techniques offers insight into the complex mineralogy and elemental composition of these natural materials.

Our results demonstrate the advantages of non-destructive analysis and sensitive methods towards the analysis of Aboriginal Australian objects.  This presentation will cover some of our recent work including the first non-destructive study of natural pigments on Aboriginal Australian objects directly at a synchrotron, micro-characterisation of mineral pigments and provenance studies with Australian ochre.

Rachel is an Australian Institute of Nuclear Science and Engineering (AINSE) Senior Research Fellow in the School of Chemical and Physical Sciences at Flinders University.