Investigation of Manufacturing and Gilding Technique of Metallic Door Facing of Masji-i Iamām, Isfahān

The art of Safavid period has always been the rich and valuable arts of the Iran which has a great important in art of Islamic period. Among the remaining monuments and relics from the Safavid period in Isfahan, Naqshi-i Jahan square is of particular importance in which Masjid-i Iamām has outstanding artistic features. So, numerous studies have been carried out on different aspects of this Masjid. However, one of the most prominent features that has not been investigated is the main door of the mosque and its metallic facing. The aims of this paper are to identify the alloy composition, manufacturing and gilding technique that have been used in metallic door facings of Masjid-i Iamām, Isfahan, in order to recognize the Safavid metalwork. For this purpose, different parts of the door were sampled and analyzed by SEM-EDS, ICP-OES and also Metallography. The results showed that an alloy of silver and copper has been used in manufacturing of metal sheet of the door. Also a very few amounts of arsenic, zinc and lead were identified in the alloy composition, which can be related to the ore extraction and cupellation process. Slip lines and twins were identify in the microstructure of the silver sheet. Accordingly, metallographic investigation showed that thin silver sheet have been made by hammering and annealing. In addition, the fire gilding (amalgam gilding) was distinguished as surface decorating technique. The presence of mercury in the gold layers and the porosity in the gold layers confirmed the use of amalgam gilding.