Characterising Chumash Rock Art Pigments Using Portable XRF Technology

Abstract

The aims in this examination were to explore the viability of using XRF technology to gather information on raw materials and preparation techniques used, to differentiate between pigments and painting events, and to discuss the social implications of this information. Five Chumash rock art sites in the Windwolves Preserve, California were examined using X-Ray fluorescence analysis in order to characterise the range of pigments used. Most of the pigments were red in colour but black, grey, blue and white pigments were also included in the study. The findings showed that this technique is viable, particularly as a quick method of identifying different pigments and painting events, and provides information from which it is possible to infer preparation techniques.

The results showed that multiple pigments were used within each rock art panel and within individual elements. It is also possible to infer from the data that some pigments were directly applied raw ochres and some had been processed, thus indicating different techniques being applied to the same panel. As such it is likely that rock art sites were revisited with rock art being added to at various times indicating that it may have been much less exclusive than has previously been suggested. This project also opened up a number of questions relating to rock art research in terms of the identification of pigment binders from the data and the possibility of utilising other analytical techniques in order to glean more information.