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 fluorescen ce (XRF) analysis. The coloured pigments, the medium and the plaster were a ll examined. The presence of potassium and calcium in all coloured layers d emonstrates that the painting technique is of a type very similar to that u sed 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 ef fects of lime on alkali-sensitive mineral-based colours.