传统西藏壁画表面涂层材质与工艺研究

Research on the materials and techniques for surface coatings on ancient Tibetan wall paintings

在前期对甘肃拉卜楞寺壁画表面涂层结构分析基础上,以桐油、亚麻油、胡麻油等干性油为基础材料,试验重现了制作西藏壁画表面涂层的“古法”清漆熬制方法和工艺。同时,提出了一种源于“古法”,吸收现代油基树脂漆优点,具有良好材料结构且组成可知、可控、兼容等特点的清漆材料及其工艺(“新古法”)。研究表征了“古法”“新古法”清漆的结构,评价了清漆涂层的颜色、外观、光学性质、艺术效果、耐候性等,并与现代合成的醇酸清漆、氟碳清漆、酚醛清漆等做了对比。结果表明,“古法”“新古法”清漆在达到与合成清漆相同化学稳定性、耐候性的同时,具有更好的兼容性和表现效果,可用于今后西藏壁画表面涂层材料的修复。

Based on the previous analysis of the surface coating of ancient Tibetan wall paintings at Labrang Monastery in Gansu,drying oils,such as tung oil and linseed oil,were employed to explore and reconstruct the procedure for making and the process for brushing traditional varnish.Also,a new varnish originating from traditional varnish recipes but combined with the advantages of modern oil-based paint is proposed.This new varnish is accessible and controllable in its structure and composition,and is compatible with the original historical surface coating.The structures of the traditional and“new-traditional”varnishes were analyzed using Fourier transform infrared(FTIR)spectrometry.The color,appearance,aesthetic effects and weatherability of the traditional and“new varnishes”were also evaluated and compared with modern synthetic varnishes,such as alkyd,fluorocarbon and novolac.The results indicate that the traditional and new-traditional varnishes have achieved the same chemical stability and weatherability as synthetic ones,while exhibiting better compatibility and aesthetic effects.These varnishes could be used as surface coating materials for Tibetan wall paintings in the future.