At the western end of the Hexi Corridor in Dunhuang, Gansu province, conservators at the Mogao Caves are injecting a specially developed material into flaking murals to stabilize the aged pigment layer.

Yu Zongren, head of the Institute of Conservation of the Dunhuang Academy, said mural restoration has seen a shift from experience-based to scientific and standardized approaches.

The harsh desert environment, with large temperature differences and frequent sandstorms, constantly threatens the thousand-year-old murals. Sand from the nearby Mingsha Mountains gradually enters the caves, causing damage.

Yu said that protecting murals is not only a technical battle against nature but also an art of balancing time. Seeking short-term results risks losing critical information, so every step must be carried out meticulously.

To ensure timeliness while preserving quality, the team has explored in-situ non-destructive analysis techniques using portable devices. However, these have limitations in sensitivity and precision. The rough, irregular mural surfaces caused by long-term wind erosion also make preventing data loss difficult.

The team adapted optical coherence tomography technology from eye exams to analyze the characteristics of materials, X-ray from orthopedics to investigate internal damage, along with near-infrared spectrometers and hyperspectral scanners. Together, they form an analysis system for complex mural scenarios.

The team has now worked on over 400 key relic protection projects.