LIBS for the Characterization of Roman Wall Paintings

Laser Induced Breakdown Spectroscopy (LIBS) has been coupled to other spectroscopic methodologies and diffraction techniques, for the identification of pigments and materials used in Roman wall paints. The investigated samples are fragment of painted plasters coming from roman villas located in the Tiber valley (Sabina area, central Italy). The combined application of LIBS with ?-Raman and Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) spectroscopies and X-Ray Diffraction, has shown to yield valuable complementary information. In particular, LIBS measurements yield information about the elemental composition of the paint plaster on the basis of its optical emission spectrum, in addition to depth profile analysis of the paint layers. As a little amount of sample is consumed (less than 1 ?g), LIBS can be considered as a micro-destructive technique. The complementary FTIR-ATR and ?-Raman spectroscopies provided IR spectra specific of the molecular structure. In the frame of an ongoing research project aimed at the reconstruction of the dynamics of Roman settlement in the Sabina, the study of these archeological findings have provided relevant contribution to the characterization of the materials and techniques used in wall paintings in the Roman countryside. In particular, they have provided historical insight and confirmed some assumptions on the use of local and cheap materials in roman rural architecture.