Digital imaging and the revelation of 'hidden' rock art: Vaalekop Shelter, KwaZulu-Natal

Abstract

Vaalekop Shelter, a small and seemingly sparsely painted rock art site on the upper reaches of the Mpofana (Mooi) River, KwaZulu-Natal, will be flooded by the construction of the Spring Grove dam downstream. In mitigation the site was photographed using a proprietary digital imaging process with the acronym CPED (capture, process, enhance and display). CPED provides different views of the rock art: a 360º view of the painted rock surfaces and their surrounds, a very high-resolution mosaic of the painted rock surface, and enhancements of the painted rock surface that reveal details of the art invisible to the naked eye. These innovations literally change the way that we look at rock art. Instead of the traditional approach to rock art photography in which many separate images are recorded of the paintings, CPED takes the painted rock surface as the basic unit of analysis and users may zoom in and out of the composite image (the high resolution mosaic) depending on the level of detail required. Rock art that was formerly considered 'indecipherable' due to the deterioration of the painted surfaces becomes more clearly visible after applying image-enhancement algorithms that produce 'false-colour' and greyscale images.