1. Conservation Department, Faculty of Archaeology; Fayoum University; Fayoum Egypt
2. The Department of Scientific Research; The Metropolitan Museum of Art; New York NY 10028 USA
3. Institute of Photonics and Nanotechnologies - Consiglio Nazionale delle Ricerche (IFN-CNR); Milan 20133 Italy
4. The Department of Objects Conservation; The Metropolitan Museum of Art; New York NY 10028 USA