Degradation processes of ancient papyruses from the Champollion collection

The objective of this proposal is to gain insight into the degradation processes taking place at the surface of illustrated papyrus from Ancient Egypt. We are investigating a series of those from Champollion’s private collection, showing scenes from the Book of the Dead. Through X-ray diffraction experiments at ID22, we identified several compounds resulting from a degradation process in addition to the classic coloured pigments used by Ancient Egyptians [1]. These degradation products consist mostly of several potassium and sodium sulphates in the yellow regions, and chloride lead-based phases in the white regions. Unfortunately, the reactions paths remain unclear due to the lack of crystalline intermediate compounds. In order to find amorphous intermediates, we intend to perform micro-X-ray absorption spectroscopy (micro-XANES) at the As and Pb edges at the BM23 beamline.