On the pigments of Egyptians: blue and green. New research and analysis on the objects of the Egyptian Museum of Turin

The presence of a wide number of fragments of blue, red, yellow and green pigments in the collections of the Museo Egizio of Torino gave birth to a specific research project on colors aimed also to the conservation of painted supports. A first series of investigations was conducted on fragments of parietal paintings dating to the Middle and New Kingdom and coming from the beginning of the last century excavations of the Museo Egizio at Qau el-Kebir, Assiut and Thebes. It was followed by further applications of this research to painted sarcophagi of the III Intermediate Period, discovered in 1903 in the Queen Valley at Thebes again during another excavations of the Museo Egizio. Data related to a non invasive approach showing statistical differences in the composition among green and blue colors are presented here. All the analysis were performed by portable X-ray Fluorescence spectrometry and Raman spectroscopy. The analyzed samples are wooden painted sarcophagi from XXIII-XXV dynasty, blue and green hues applications on wooden sarcophagi from XI and XII dynasty and a series of cakes of raw pigments. For what concerns Egyptian blue, research has also been extended to its heritage in the ancient Roman world as the “caeruleum” cited in the classical bibliographic sources, drawing the attention to its attestations as raw material. In particular, the multivariate analysis of the data shows a systematic correlation between SiO2, CuO and CaO that allows to distinguish (supported by other impurities) the chemical composition of different pigments, adding new data to the international studies on green and blue colors. The goal of this work concerns the knowledge improvement on green and blue manufacturing in the context of archaeological finds coming from the excavations of Assiut, carried out by Museo Egizio among 1905 and 1910, in the framework of the scientific recovery of materials of the excavation set up in collaboration with Società Cooperativa Archeologica (SCA), who offered to support and contribute to the scientific study, conservation and enlighten of the work path.