X-ray diffraction and SEM Investigation of Wall Paintings Found in the Roman Temple Complex at Horvat Omrit, Israel

In the present study, the fragments of wall painting found in the Roman Temple Complex at Horvat Omrit were analysed for the first time using the non-destructive techniques of X-ray diffraction (XRD) and scanning electron microscopy (ESEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The application of these methods enabled unambiguous identifications of the pigments and plaster components of the samples. Quantitative information on mineral composition, crystallite size and elemental composition of each studied paint layer and plaster was collected. Based on the results of the XRD and EDS analyses, the green pigment was identified as celadonite. It was revealed that the Egyptian blue pigment does not contain impurities of tin and lead, and this excludes the use of bronze scrap in its synthesis. Comparison of the mineral composition of the paint layers indicates that a wider palette of colours was obtained by mixing the available mineral pigments. The study of cross-sections of painted specimens revealed the usage of slaked lime for plastering. The obtained results give a new insight into the wall painting technique employed by ancient artists at Horvat Omrit, in northern Israel.