title: Microchemical Study of Pigments and Binders in Polychrome Relics from Maiji Mountain Grottoes in Northwestern China.
abstract: In this study, an integrated analytical method was developed to investigate the composition of both the inorganic pigments and organic binders of polychrome relics in Maiji Mountain Grottoes in northwestern China. Cross-sections of each sample were prepared at the beginning of the study, and all experiments were carried out on these cross-sections. Polychromic structures were revealed by optical microscopy and scanning electron microscopy-backscattered electron imaging. Inorganic materials were determined by using SEM coupled with an energy dispersive spectrometer and μ-Raman spectrometer, whereas organic materials were identified by staining techniques and highly sensitive and specific immunofluorescence microscopy. Data showed that the red colors are attributed to one or two pigments of red ochre, cinnabar, and minium; the blue pigment is natural lazurite; the green pigment is ascribed to atacamite; the white color is attributed to potassium feldspar; and the black surface is formed by the discoloration of minium to plattnerite under the influence of environmental factors. Regarding organic binders used in painting and preparation layers, mammalian animal glue and chicken egg white were both found alone or in mixture. Finally, the conclusion is made that the Secco technique is employed in polychrome relics from Maiji Mountain Grottoes.
authors.affiliation: 1Department of Chemistry,Zhejiang University,Hangzhou 310027,Zhejiang Province,P.R. China.
authors.forename: Luyao
authors.initials: L
authors.lastname: Liu
authors.affiliation: 2School of Environmental and Chemical Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,Jiangsu Province,P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.affiliation: 1Department of Chemistry,Zhejiang University,Hangzhou 310027,Zhejiang Province,P.R. China.
authors.forename: Bingjian
authors.initials: B
authors.lastname: Zhang
authors.affiliation: 5Maiji Mountain Grottoes Art Research Institute,Tianshui 741000,Gansu Province,P.R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Ma
keywords: Maiji Mountain Grottoes; binders; pigments; polychrome relics; secco fresco