3.10 Chumash Indian Rock Art: A Study of Pictograph Pigments in the Collections of the Santa Barbara Museum of Natural History

Internal Report to John Johnson,
Head of Anthropology, Santa Barbara Museum of Natural History
David A. Scott
The Getty Conservation Institute
Period of Activity: 1988-1991

Project Abstract
The report summarizes the initial work conducted on the rock art pigments for important, primarily Chumash Indian, sites in the vicinity of California. The purpose of this study was the analysis of fifteen red and yellow pigment samples by polarized light microscopy and energy dispersive X-ray fluorescence spectroscopy energy dispersive. Further work concerning the characterization of these pigments was carried out by X-ray diffraction and the pigments were primarily identified as red ochres and yellow ochres. X-ray powder diffraction work was carried out on a number of the pigment microsamples with the result that many of them proved to be admixtures of quartz and haematite. Components such as goethite or lepidocrocite were comparatively less common in this material suggesting that the source of the pigment was either a relatively pure haematite or that some conversion to haematite had been deliberately created. Common impurities from the Santa Barbara Channel Island areas include albite or anorthite. Color photomicrographs are given of the typical pigment materials and further work is envisaged on a number of related pigment samples in the collections of the American Museum of Natural History in New York.