Abstract. Scientists and conservators, involved in cultural heritage documentation management, have to furnish not only qualitative but also quantitative description of the assessment of state of conservation that is incomplete without a realistic estimation of degradation conditions. Scientists and technicians, involved in analytical analysis, are able to satisfy these needs through stone or paints sampling analysis, often destructive when approaching a monument. The paper refers to the application of the Digital Image Processing and non-invasive damage analysis (ICAW technique) employed to verify in qualitative and quantitative way the decay of stone and rock paintings.