Analysis on the composition/structure and lacquering techniques of the coffin of emperor qianlong excavated from the eastern imperial tombs

Abstract

This article presents the results of an investigation on the coffin of Emperor Qianlong excavated from the Eastern Imperial Tombs of the Qing Dynasty in Zunhua, China. The composition, structure and lacquering techniques used in the manufacturing process were analyzed in this project. Stereoscopic Microscopy, SEM-EDS, XRD, FTIR, Raman, Double-shot Py-GC/MS were used as scientific analytical methods. The results show that the structure of the coffin body consists of a wooden body layer, a lacquer ash layer and a lacquer film pigment layer. The lacquer ash layer consists of nine stucco layers and ten fiber layers on top of each other in an alternating order. The lacquer film pigment layer consists of mineral pigments, lacquer sap, animal gelatin, drying oil, quartz sand and proteinaceous materials. Pigments used in the lacquer film include calcite white, carbon black, cinnabar red and gold. The presence of three distinctive catechols along with the other catechols' and phenols' profiles in the lacquer film matrix clearly indicate the species of the lacquer tree was Rhus. Vernicifera. Several distinctive lacquering techniques that improved the coffin body's stability and mechanical strength were identified in the investigation, including the "wan lacquering", "painting lacquer above the gold" and "Jin Jiao".