Wall Paintings Conservation at Mogao Grottoes
Regular post-treatment monitoring for changes in condition is imperative as the causes of deterioration, soluble salts, are still present, and mitigation of deterioration depends on environmental control.
Post-treatment condition monitoring programThe nature and extent of treatment undertaken in Cave 85 requires the implementation of a post-treatment condition monitoring plan. The principal remedial treatments of the wall paintings, injection grouting and soluble-salt reduction, were undertaken on a large scale, reflecting pre-treatment conditions of extensive areas of plaster detachment and widespread salt contamination of the plaster and rock substrate. The scale of the interventions was matched by their high-risk nature. Grouting is both an invasive and imprecise intervention. Similarly, the reduction of soluble salts is also potentially hazardous, risking the redistribution of soluble salts, particularly in the case of earthen plasters. Moreover, remedial treatment was not a means of halting the complex and diverse range of environmental deterioration processes in the cave. Thus, a condition monitoring strategy must also reflect the continuing vulnerability of the plaster and paint materials, and anticipate all other aspects of potential future deterioration.
High resolution post-treatment documentation photographs, photographic details in incident and raking light, post-treatment graphic documentation, and written notes of specific monitoring areas provide the basis for assessing change. The monitored areas included representative examples of all recorded deterioration phenomena, and both treated and untreated areas. Given the difficulty of assessing painting condition, training of personnel is a critical component of the monitoring program.