The Redecoration History of a Chinese Polychromed Guanyin Attributed to the 11<sup>th</sup>–12<sup>th</sup>Century C.E. as Deduced from Stratigraphic Microanalysis
ABSTRACTThe decorative polychrome history of a remarkable depiction of the “Guanyin of the Southern Sea” dating to the 11th-12thcenturies C.E. (Nelson-Atkins Museum of Art, Kansas City, #34-10) has been studied by integrating the results of Scanning Electron Microscopy with Elemental Analysis by X-ray Spectrometry, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy and Polarized Light Microscopy. This 2.4m by 1.65m sculpture, carved almost entirely from a single Populus tree, has been attributed to Northern China and offers important points of comparison to previously studied works in the Victoria and Albert Museum and Rijksmuseum, with which it differs in certain important respects. Evidence for the original polychrome color scheme and those of at least three successive historical redecorations (two of which have been assigned ages by radiocarbon dating of paper interlayers) was found throughout the figure. By integrating the different forms of information obtainable from the methods cited above, it was possible to more fully describe complex pigment mixtures used to render different parts of the draperies. Both fracture sections and prepared cross sections serve different functions in revealing aspects of the paint preparation and its subsequent alteration. The differentiation of polymorphs of copper trihydroxychloride, made possible by Raman spectroscopy, allowed us to identify manmade botallackite with distinctive particle morphology as an important pigment of the intermediate period decorations, while elemental analysis of tin oxide traces showed that manmade atacamite used in other colors was derived from corroded bronze. Elemental analysis allowed distinctions to be made in the shade of gold leaf applied in different periods from cross sections without divesting the sculpture of later paint applications. The cross sections also provided evidence for the existence of flat gold line-work in areas subsequently redecorated with raised gilt brocades. Several combinations of the organic pigment indigo and inorganic paint constituents such as lead white, azurite, malachite and quartz reveal the means of adjusting shade and optical effects in closely-related paint applications. The results obtained by employing complementary techniques of analysis have served to greatly expand our understanding of the original use of polychrome decoration in the late Liao or Jin periods and its subsequent evolution, while alerting us to important Chinese innovations in the manufacure of pigments.
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