Non-invasive analysis of mural paintings from a late-Republican house in Ostia

This paper is a comprehensive analytical study of the murals belonging to an ancient Roman house through the characterization of materials. The project focuses on the wall paintings of the Domus dei Bucrani - a house of the end of the Republican era discovered on the site of the Schola del Traiano in Ostia. This domus has undergone several phases of development in the 1st century BC before being destroyed around 20 BC. A new house was immediately rebuilt after a major change from the ground, which allowed exceptional preservation of the decoration system. The results complement our knowledge of Roman painting techniques during the 1st century BC and also provide a comprehensive multidisciplinary approach to the problem of conservation of wall paintings. These two related objectives have been studied using non-destructive testing methods (MA-XRF, FTIR and Raman spectroscopy). The analyses have been performed in situ using our mobile systems. The different set-ups had to be modified in order to be able to work on horizontal surfaces, specially our XRF scanner. The study of the pictorial layers address various issues in the field of archaeology: what technique has been implemented? Does the same technique was used in both phases of the development of the domus? Do they correspond to the techniques described by ancient writers? These responses are compared to those observed in other sets of murals dating from the 1st century BC.