Rupestral paintings of the "La Graja" cave. Pigment characterization and digital image analysis

Abstract

The present study is part of a wide-ranging research on a group of archaeological sites located in Andalucía (Spain) whose main aim was a better understanding of these sites within a geomorphological, biological and climatic context. This specific investigation concerns the alteration processes affecting the rupestral paintings found in the cave of "La Graja". It has been concluded that such processes are related mainly to the high availability of water at the site's location. The paint's composition diverges from that usually encountered in other, previously studied shelters, where iron oxides have been found to prevail. The presence of copper oxides, titanium and cerium represents a departure from the common findings in Andalusian rupestral paintings.