Contribution from SEM Studies in the Understanding of Degradation Mechanisms of Copper Green Pigments from the Louvre Museum's 21st Dynasty Egyptian Coffins

The 21st Egyptian Dynasty marks a big change in funeral practices. Decorations with Gods’ representations and magic formulas to help the deceased in his journey to afterlife are no longer on walls but directly on the coffin itself; which acts as an entire grave. Coffins were stored in long corridors, resembling mass graves. Egyptian Yellow Coffins are therefore a very specific production only found in the Theban area and reserved for the priests and priestesses of the Amun Temple. The study of these objects, a part of the Vatican Coffin Project, has as a main goal to identify all the materials used in order to determine the manufacturing process. A global view of this characteristic production will allow us to isolate and maybe even identify specific workshops. For this purpose a multiscale and multispectral methodology for analysis has been developed at the Centre de Recherche et de Restauration des Musées de France. In cultural heritage studies analysis are done in two steps: in-situ ones and those done on micro-samples which are micro-flakes, having a size of less 1mm². Each sample is performed to answer a precise question about the object. As an invasive procedure, very few are done. They are then unique and also very fragile. A dozen funerary sets from the Egyptian Antiquities Department of the Louvre Museum are under study. SEM imaging and SEM-EDS analysis have proved to be very helpful for the chemical characterization and also the identification of degradation mechanisms of green pigments.