A non-destructive analytical study of a recently discovered Roman wall painting

A Roman wall painting of the first century AD, recently discovered in Rome, has been studied extensively, in situ, by non-destructive X-ray fluorescence (XRF) analysis. The coloured pigments, the medium and the plaster were all examined. The presence of potassium and calcium in all coloured layers demonstrates that the painting technique is of a type very similar to that used in Pompeian wall paintings, and described in the 1950s by Selim Augusti. In this type of wall painting, the pigments were dissolved in a lime/soap/water solution, the function of the soap being to mitigate the negative effects of lime on alkali-sensitive mineral-based colours.