Research On The Conservation Of Color-painted Sculptures Of The Tang Dynasty Of Foguang Temple In WuTai

Foguang Temple is the largest and best-preserved wooden architecture of the Tang Dynasty.It was placed on the first batch of key cultural relics protection units in 1961.The Main Hall of Foguang Temple remain 35 color-painted sculptures of the Tang Dynasty.Which are the most valuable artistic products among Chinese temple sculptures with the highest grade,the largest scale and the most complete combination.After thousands of years,these sculptures have occurred many deteriorations because of the damage of the Main Hall.Protection task is very urgent.However,there are few researches on the conservation of the sculptures in Foguang Temple.Also there are no reliable scientific bases to repair them.Basing on the current situation investigation and the research of traditional materials and craft,we analyzed the causes of deteriorations and gave suggestions in order to protect the sculptures better.In addition,we have tested different properties of 5 kinds of conservation materials in order to find the best choices for treating the scuptures.The research primarily has the following results:The current situation investigation showed that changeable weather,large diurnal temperature and high humidity have caused the negative influence to the conservation of sculptures.Surface deteriorations such as the faded,flaked,cracked,peeled,coveraged and structural damage such as fractured,cracked,soil loss are becoming worse and worse at present.Analysis of materials and craft showed that this group of sculptures was re-painted many times,the painting can be divided into 3 layers,painted in Tang,Ming and Qing Dynasty,and Modern times,respectively.Carbon black,cinnabar,Malachite and white lead were used in Tang Dynasty;Hematite,Malachite,Lazurite and azurite in Ming and Qing Dynasty;Red lead,emerald green,Lazurite and orpiment in Modern times.The painting craft in different times was also different.This mainly caused the deteriorations of the painting layer.It is highly possible that the materials used to make sculptures were collected from local area because mineral composition and relative content of the soil is much closed to the local soil samples.It is worth mentioning that small amount(about 11%)sand was detected in the soil and the hemp fiber and pulp were found in different layer.This suggests that as early as the tang dynasty,Chinese craftsmen had already begun to notice the importance of the balance ofplasticity and strength ofsoil.Analysis of deterioration found that the main external factors that caused the disease of sculptures are temperature,humidity,animals and microorganisms,and the main internal factors are the difference of materials,the content of the clay mineral and the soluble salt.Five kinds of conservation material which are widely used were employed to reinforce the simulated samples.The color retention,permeability,air permeability,water absorption,shrinkage and compressive strength were tested to screen reinforcement materials that suitable to painted sculpture of the Main Hall.The results indicate that silicone-based material Pelik and traditional material isinglass are ideal choice.