The development of effective conservation strategies for the protection of rock art sites involves the assessment of the taphonomic risks posed by physical and chemical weathering. This study outlines the methodology used in a pilot study to monitor and model the deterioration of paint residues in a cave environment. Mineral oxide pigments were mixed with water and placed on the walls of a cave in the Mendip hills (UK). The physical degradation of the paint residues was simulated visually and modelled mathematically. A training stage learning the characteristics of a reference image is followed by comparisons with this image as the test paints deteriorate. The study will be extended over three years and digital image processing will be used to quantify changes in the colour and dimensions of the test paints. The results will be correlated with micro-climatic variables. This methodology can be used to model taphonomic changes to rock art and other forms of imagery in differing environments.