Papier peint Pigments Analyse scientifique Technique (art) Gugong Yucui Xuan pizhi chengfen fenxi yu gongyi yanjiu 故宫玉粹轩壁纸成分分析与工艺研究 = The Component and Craftwork Analysis of the Wallpapers of Yucui Xuan (Pavilion) of the Forbidden City