陕西旬邑西头遗址出土彩绘白灰面的成分和工艺分析

Material and technical analyses of painted plasters excavated from Xitou site in Xunyi County

对陕西旬邑县西头遗址出土的彩绘白灰面进行了成分和制作工艺分析。采用偏光显微分析、扫描电镜能谱、X射线衍射,拉曼光谱分析了该彩绘面的颜料和石灰层成分,采用气相色谱-质谱联用技术(GC-MS)分析了该彩绘面的胶料成分。结果表明,该彩绘面的颜料由铁红,铁黄和绿土构成。白灰层由碳酸钙构成,部分样品中存在双层白灰层。GC-MS分析表明,该彩绘面的胶料含动物胶,可能还含蛋类。通过比较研究发现,旬邑彩绘白灰面的制作工艺和与后期壁画制作工艺相似,对其组成和工艺的研究将有助于探索先周时期关中地区壁画的起源和发展。

Our study dealt with the material and technical aspects of newly discovered painted plaster fragments excavated from Xitou site in Xunyi County,Shaanxi Province(Xunyi is one of the earliest birthplaces of the Zhou Dynasties).A multi-technical approach was employed to identify the inorganic and organic materials in the painted plasters.The plaster layer and pigments were investigated by means of polarized light microscopy,scanning electron microscopy-energy dispersive spectrometry(SEM-EDS),X-ray diffraction(XRD)and Raman spectrometry.The results show that the pigments are iron-based ones(red and yellow ochre)and green earth.The plaster layer is mainly consisted of calcite,while a thin lime mortar forms the backing between the lime plaster coat and the painted layer in some samples.The adhesive ingredients were analyzed using gas chromatography-mass spectrometry(GC-MS).The results show that the binding materials on the painted plaster contain animal glue and perhaps egg.In addition,through comparison,it was found that the technique used for the painted plasters in Xunyi was similar to that used for other typical Chinese archaic murals.This study could help us explore the origin and history of murals in Guanzhong area during the pre-Zhou period.