The ongoing project for the conservation of wall paintings at the Mogao grottoes, a collaboration of the Getty Conservation Institute and the Dunhuang Academy, continues this spring with a six-week campaign.
The project has posed great technical challenges. Among the most taxing problems is the extensive detachment of the one-inch-thick painted mud plaster from the conglomerate rock into which the cave temples are cut. This problem is pervasive in the site's 500 caves. In Cave 85, the large Tang dynasty grotto selected by the Dunhuang Academy and the GCI as the model for the development of a conservation methodology, large areas of wall painting have separated and require grouting to reattach them to the rock.
This spring, members of the project team will return to Cave 85 to begin grouting of the wall paintings. After extensive lab and simulation testing of some 80 grout formulations, a grout was selected for use. Because the grout is water-based, it will mobilize damaging soluble salts, mainly sodium chloride, bringing them to the surface. Solving this problem requires simultaneous grouting and poulticing to remove salts. Special presses to hold the poultice packs in place as the grout sets and dries have been developed, and the efficacy of poulticing is being monitored.
With completion of the physical conservation of Cave 85, expected by mid-2003, it is hoped that the cave will be presented to delegates at the Second International Conference on the Conservation of Silk Road Sites, scheduled for August 2003 (see Conservation, vol. 16, no. 2). Some 200 delegates are expected to attend the weeklong conference, which will focus on wall painting conservation, China Principles-based planning methodology, and visitor management issues.
The Mogao grottoes have also played an important role in the development of the China Principles, China's national guidelines for conservation and management of sites, developed by China's State Administration for Cultural Heritage (SACH) and the GCI, in collaboration with the Australian Heritage Commission. The long-standing relationship between the GCI and the Dunhuang Academy, and the support of the Academy's director Fan Jinshi for the Principles, has led to the selection of Mogao for the application of the Principles to the master planning for the site as a whole. The bilingual plan has been completed and will be presented to senior personnel of SACH in Beijing this spring. The process is expected to become a model for Chinese site plans.
In an additional undertaking, the China Principles implementation team at Mogao—the GCI, the Dunhuang Academy, and the Australian Heritage Commission—are developing the visitor management component of the master plan. Now readily accessible to visitors, Mogao is rapidly being transformed into one of China's premier tourism venues. The goal of the Principles team is to determine the safe carrying capacity for the site so that the fragile wall paintings and desert environment will not be adversely impacted by overuse. This multifaceted undertaking involves research in environment and condition monitoring in selected caves, visitor surveys, analysis of interpretation needs, and development of a safe lighting system prototype for the caves.
In a further development for conservation in China, the Dunhuang Academy and Lanzhou University have recently signed a protocol to establish a postgraduate wall painting conservation training school. Professor Sharon Cather from the wall painting conservation program of the Courtauld Institute of Art in London and staff from the GCI are providing advice on curriculum development. Detailed discussions will be held during the spring campaign at Mogao.