A Micro-Analytical Approach for Pigments Identification on Qajarid Wooden Panels in Isfahan: Identification of Conichalcite as a Degradation Product of Emerald Green

Document Type : Original Article

Authors

1 Tabriz Islamic Art University

2 Art University of Isfahan

Abstract

Decorating Iran's historical monuments often involves painting on wood, an area relatively underexplored in research. Examining the color palette utilized by artists in these works can offer valuable insights into the era's commercial, cultural, and economic milieu, while also aiding in identifying deterioration processes and proposing conservation strategies. This study seeks to determine the pigments employed in the paintings on wooden panels of the Shahsavaran House, a structure dating back to the Qajar period in Isfahan city. Utilizing micro-Raman spectroscopy and micro-XRF spectroscopy, the pigment composition of white, green, blue, yellow, and red hues was analyzed. The findings revealed a preliminary layer of white lead applied to the wood surface, followed by the painting execution. Examination of the pigments unveiled the presence of white lead, red lead, chrome yellow, and ultramarine blue. Notably, the green pigment was identified as conichalcite, a pigment not commonly utilized, likely arising from the degradation of emerald green. Furthermore, the presence of massicot alongside white lead in white areas suggests the degradation of white lead in an outdoor environment. The identified pigments in this artwork include lead white, lead red, and ultramarine blue, which are traditional and commonly used pigments in Iranian art-historical works. However, through the identification of chrome yellow and the potential use of emerald green, it is estimated that the paintings can be dated from the mid-19th to the mid-20th century.

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