Spectroscopy and Spectral Analysis, Volume. 40, Issue 10, 3199(2020)
Pigment Identification of Sleeping Buddha at World Cultural Heritage Dazu Rock Carvings With μ-Raman Spectroscopy and Related Research
Niche of Sakyamuni Eentering Nirvana (Sleeping Buddha) at Baoding mountain, Dazu District, Chongqing, is the largest statue in Dazu rock carvings, one of the world cultural heritage, and also the world’s largest Buddha statue featuring only the upper part of the body. Suffered from the influence of natural power and human factors for thousands of years, various diseases such as paint scaling and biological colonization appeared on the surface of the Sleeping Buddha. To achieve the conservation and restoration of “raw materials and original technology”, it is necessary to identify the pigments of the statue. The surface pigments and the priming coat material of the Buddha were identified by means of micro-Raman spectroscopy (μ-Raman) and other techniques. Furthermore, the possible sources of white and green pigments, the relationship between pigment types and mildew have been discussed. The experimental results have shown that the back of each surface pigment of the Sleeping Buddha based on white priming coat material. The Raman spectrum of the priming coat material shows an intense band at 1 006 cm-1 without other additional bands, which is the characteristic band of gypsum, that indicated the primer material is gypsum (CaSO4·2H2O) with high-purity. The surface of the statue is decorated with red, blue, white, and green pigments. The red was identified to be red ochre (Fe2O3), with stable property and widely used in various painted relics, such as murals and painted pottery. Combined analysis by polarized light microscopy, the blue was identified to be synthetic ultramarine blue (Na6-10Al6Si6O24S2-4), with uniform particles and averaging less than 5 μm in diameter. The white was identified to be a mixture of cerussite lead white (PbCO3) and mimetesite (Pb5(AsO4)3Cl). Among white pigments, lead white is common, while mimetesite is infrequent. In particular, mimetesite is discovered as pigment for the first time at Dazu rock carvings. The Raman spectrum of green pigment displays intense bands at 859 cm-1, attributed to the As
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Li-qin WANG, Yan-ni MA, Ya-xu ZHANG, Xing ZHAO, Qiu-ju HE, Jin-yi GUO, Han-ting REN. Pigment Identification of Sleeping Buddha at World Cultural Heritage Dazu Rock Carvings With μ-Raman Spectroscopy and Related Research[J]. Spectroscopy and Spectral Analysis, 2020, 40(10): 3199
Category: Research Articles
Received: Jan. 13, 2020
Accepted: --
Published Online: Jun. 18, 2021
The Author Email: WANG Li-qin (wangliqin@nwu.edu.cn)