Measurement of the reversible rate of conservation materials for ancient murals

The study of how to remove the ineffective conservation materials without damaging the mural's surface has been one of the hot issues of modern conservation science, and the reversibility problem of mural protective materials needs to be resolved instantly. In this article, we measured the reversible rates of 4 typical protective agents both on glazed tiles and model samples of Dunhuang murals, and used 3D microscopic system to observe the removal effect. The experimental results show that the cleaning agents should not contain water considering the water-soluble binding material of Dunhuang murals. All conservation materials are reversible, but their reversibilities are different. We obtained the best pairs of “conservation material-cleaning agent”, which are “silicone-acrylic emulsion-p-xylene   +   propylene carbonate”, “acrylic emulsion-p-xylene”, “polyvinyl acetate emulsion-p-xylene   +   ethyl acetate” and “Paraloid B72-p-xylene   +   propylene carbonate”. It is also found that the reversible rate of conservation materials declines after aging.