Excessive fixative treatment done in the past has caused much damage to the murals of the Payathonzu temple in Myanmar. In this study, the fixative components treated on the mural paintings of Payathonzu temple were analyzed, and the applicability of the gel cleaning system was analyzed to remove them effectively and stably. Six types of gel cleansers were prepared by mixing three types of gelling agents (Nevek®, Laponite®RD, Carbopol®980) and two types of organic solvents (Acetone, Dimethyl carbonate), and their properties and removal degree were measured. In addition, gel cleaners were applied to the test specimens imitating the material of the mural paintings of Payathonzu temple, and the cleaning effect and the stability of the painting layer were evaluated assuming when applied to the actual mural paintings.
A py-GC/MS analysis of the fixative treated in the Payathonzu temple mural paintings turned out to be PVAc [poly(vinyl acetate)]. As a result of testing the removal degree against PVAc with the prepared gel cleaners, it was found that the removal effect varies depending on the types of solvents and gel cleaners used in the preparation, and the application time of the gel cleaners. The higher the solvents'' solubility and volatility, the better the removal effect. Since the viscosities of the gel cleansers vary the speed of availability of the fixatives and the degree of evaporation of the solvents, the removal degree differed depending on the type of gel cleaner even if the same solvent was used.
As a result of analyzing the cleaning effect of gel cleaners on simulated specimens produced under conditions similar to Payathonzu temple mural paintings, it showed similar results to the removal effect of gel cleaners on PVAc. However, even though the prepared gel cleaner showed excellent removal ability for PVAc, the fixative showed residual or re-infiltrating the specimens in the applicability test for the simulated specimens. This was judged as the result of the gel cleaner''s characteristics interacting with the characteristics of the mural and the fixative penetration.
In conclusion, it was found that the properties of the gel cleaner that have the greatest influence on fixative removal are solvent solubility to fixative, volatility of the solvent itself, and solvent release control. It has also been found that the materials and painting techniques of murals can be affected by cleaning. When painted by secco techniques, such as the mural painting of the Payathonzu temple, the pigment in the painting layer may be peeled together with fixative, depending on the cleaning material and technique. Therefore, in order to safely remove the fixative treated on the mural paintings of Payathonzu temple, the following points should be noted: The stability of the painting layer should be secured by the application of a controllable cleaning method by the handler. In addition, it is necessary to select a cleaning agent with properties that can effectively remove the fixative. It is expected that the research methods and results presented in this study can be used as basic data for fixative removal applied to various murals in Korea.