Non-destructive and in situ analysis of Egyptian wall paintings by X-ray diffraction and X-ray fluorescence portable systems

The concurrence and complementarities of obtained images under various wavelengths and the elemental and structural analyses provided by XRF and XRD, using portable non-invasive systems, have allowed for obtaining accurate data about the employed pictorial technique in two Egyptian wall paintings dating from the New Kingdom. Thus, compounds such as Egyptian blue, Egyptian green, goethite, jarosite, hematite, calcite, anhydrite or huntite have been detected in the paintings. The performance of the measurements by the different techniques and its contribution to the knowledge of the materials are discussed. They notably give a clue on the origin of arsenic compounds, unexpectedly detected in some decors.