Technical Study of Different Layers of Decorative Murals of Imamzadeh Hossein in Qazvin

Among the architectural arrays of Imamzadeh Hossein in Qazvin that can provide valuable information to researchers, are the remaining parts of the murals. Considering that Qazvin was the capital during the second period of Safavid rule, the study of Safavid and Qajar period buildings in this city can be of great importance. Compared to the existing historical monuments, few studies have been done on the technical knowledge of the layers of historical murals.In the present study, the identification and recognition of pigments related to the remaining murals of this monument and gilded layers has been considered. Also, in order to complete the technical information of the murals, the mortar of the fine coat (finishing plaster) and scratch coat (levelling coat) under the paint has been studied in terms of structure and chemical composition. To identify the pigments used in the murals as well as the materials used in the mortar of the underlying layers of the mural and the floor mortar, the hydraulic properties and the mineral and chemical composition of the mortar from X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy and digital microscope have been used. As a result of the studies, it was found that the Pastiglia in the murals is made of a mixture of gypsum and Bole (Armenian Bole, Hormoz Bole). Apply a white Primary layer on the pastiglia on which the gold leaf is applied with low copper impurity. In this murals, three types of gold sheets have been executed. Green: A mixture of arsenic pigment with azure blue and Prussian blue; Green-blue: a mixture of green earth pigment (Celadonite) with white lithopone; Blue: a mixture of azure and Prussian blue pigments with White lead; Red: A mixture of ocher red and orange arsenic; Primary layer filler: a mixture of Huntite and White lead; black: It is a mixture of cobalt black and iron black. The structure and composition of mortars were also identified.