The mural execution technique of the “dei Fornai” cubicle revealed by laser cleaning

During 2010 a conservation-restoration intervention was carried out in the “dei Fornai” cubicle in the Domitilla Catacombs, in Rome. This presents a particularly monumental space and a unique pictorial decoration because of the subjects and topics represented. A dark film based on calcium carbonate covered the painted decoration. Due to its extreme tenacity and the difficulty of removing, it was decided to apply a cleaning protocol using laser technology. After this, some unexpected details relative to the technical execution of the paintings emerged. The tests carried out on the pigments also showed particularly meaningful information that can be associated with the art-historical and iconographic studies concerning the cubicle. The presence of mixed colours denotes amplitude in the colour range, quite unusual according to the standards registered on catacomb painting. This information confirms, therefore, the advanced hypotheses about the allocation of the cubicle to a socially-high customer.