Analysis of Painted Materials and the Latest Repaint Time of Arhat Statues in Zijin Nunnery, China

The arhat statues of Zijin Nunnery in Suzhou are painted clay statues considered to be ancient Chinese treasures, but there has been little investigation into the materials used in their manufacture along with a general lack of systematic and scientific knowledge regarding these statues. We attempted to address this deficiency in our study described here, where the materials comprising the pigment layer of the colored statues were characterized using a variety of techniques, including X-ray fluorescence, X-ray diffraction, micro infrared spectroscopy, and micro Raman spectroscopy. A range of contemporary synthetic pigments, such as chrome yellow, emerald green, and artificial ultramarine, was discovered to be available in addition to conventional inorganic pigments such as cinnabar, minium, and azurite. Analysis of the massive statue in the main hall showed that shellac is used as a surface sealing compound on the painted clay statue and beeswax as a bonding medium for the pigment layer. Following an extensive investigation into the synthetic pigments, it was determined that the painted statues of Zijin Nunnery were painted during the most recent era of the late Qing Dynasty.