Material analysis of the wall paintings in Xialu Temple, Tibet Autonomous Region, China

This wall paintings technology study in Xialu Temple was carried out by in situ investigations and laboratory analysis. The techniques used to analyze pigments, ground/white preparations, and binding media were: optical microscopy carried out with visible reflected light and ultraviolet light; polarized light microscopy; micro-Raman spectroscopy; micro-Fourier transform infrared spectroscopy; and scanning electron microscopy. The characterization of pigments, including the discovery of two rare organic pigments, improves knowledge about traditional Tibetan paintings. The analysis of the binding media and different types of ground/white preparations (asbestos, kaolin, and illite) allowed us to identify different stratigraphic compositions. Our findings indicate that the study areas were painted during at least four different time periods.