Characterization of mural paintings from Motza and Caesarea Maritima, Israel: Insights into techniques and materials

This thesis presents a detailed investigation of the mural paintings excavated from the archaeological sites of Motza and Caesarea Maritima, Israel. The primary objective is to analyze fragments of wall paintings to discern the painting techniques employed, identify the pigments used, and determine the composition of the mortars. To achieve these aims, cross-sections were prepared from representative parts of each fragment, allowing for a thorough microscopic analysis of the stratigraphy, pigment distribution, and mortar composition. Optical microscopy provided initial insights, revealing the layering, pigment lumps, and characteristics of the mortars. Subsequently, micro-Raman spectroscopy was utilized to define the chemical composition of both pigments and mortars. This technique offered precise identification on the composition of most of the pigments, including yellow, black, and red. Nevertheless, it yielded limited data for colors such as green and blue, characterized by weak Raman signals. In such cases, and for further confirmation and detailed analysis of the already determined compositional and textural features, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) was applied, providing comprehensive microstructural and microchemical information on the analyzed samples. Additionally, X-ray diffraction (XRD) was utilized to examine the mineralogical composition of the painted surfaces. This approach provided valuable insights into the mineral phases present within the paint layers, aiding in understanding the source of raw materials and potential alteration processes over time. Moreover, XRD analysis of powder fractions from the mortar components elucidated their mineralogical composition, offering further understanding of the geological sources and production techniques utilized in mortars’ preparation. Through this multidisciplinary approach, this study provided significant insights into artistic techniques, material composition, and construction practices employed in ancient sites of Motza and Caesarea Maritima. The findings enrich our understanding of the cultural heritage of the region, shedding light on the artistic practices and technological knowledge of past civilizations.