More Than Meets the Eye: Fluorescence Photography for Enhanced Analysis of Pictographs

The study of rock art has traditionally focused on the analyses of style and technique rather than of materials and technology, in part because it is often considered undesirable to remove pigment samples for laboratory analysis. Pictographs and petroglyphs, more than many other potentially diagnostic artifacts, are often seen as one of a kind, finite resources that need to be spared from even the minimal damage caused by procedures such as X-ray fluorescence and radiocarbon dating. As such, only a limited amount of data have been generated in the last twenty years that deal with the technology involved in the manufacture of rock art. However, recent advances in photography-based procedures involving digital image enhancement (Clogg et al. 2000) and multispectral imaging (Kamal et al. 1999) have successfully highlighted the possibilities of using non-conventional photographic techniques as in situ methods of analysis, and are currently supplying new information about aboriginal pigment and stone working technologies to the field of rock art studies. As will be shown below, ultraviolet fluorescence photography also warrants consideration as a non-destructive, on-site procedure that can yield valuable data for rock art pigment recording and analysis