Non-invasive analysis and large scale imaging of murals at the UNESCO World Heritage Site of Mogao caves in Dunhuang
The UNESCO World Heritage Site of the Mogao caves, along the ancient Silk Road, consists of 492 richly painted Buddhist cave temples dating from the 4th - 14th century. The 45,000 square metres of wall paintings in nearly 500 caves are an immense resource for the study of the history of art, architecture, religion, technology, politics and cultural exchange.
The wall paintings of this historical site are vulnerable and, therefore, any inspection needs to be non-invasive and non-contact.
The aim of this project is the development of a methodology for the non-invasive and in situ analysis of the large scale murals, even when they are located in unreachable areas (e.g. ceiling). Our research was mainly focused on the analysis of cave 465 murals. Cave 465, located at the northern end of the site is unique in its Indo-Tibetan tantric Buddhist style, and like many other caves, the date of its construction is still under debate.
Mogao Caves, an UNESCO World Heritage Site in Dunhuang, China
Addressing the Challenge
The collaboration with the Dunhuang Academy was initiated in 2011, and since then the ISAAC mobile laboratory has visited the site of the caves several times, applying a range of non-invasive imaging and spectroscopic analytical techniques. More specifically, spectral imaging has been applied on large mural surfaces using the PRISMS system in the telescope configuration.
This enabled the imaging of painted areas located also on the ceiling of the caves. Hyperspectral imaging has been also applied on areas of special interest, using the high resolution version of PRISMS system in the telescope configuration.
The ISAAC mobile laboratory in cave 465, Mogao caves
OCT (Optical Coherence Tomography) scanning enabled the high resolution, depth resolved examination of the paint layers structure and sequence. Moreover, a range of spectroscopic techniques, from FORS to Raman and XRF spectroscopies, were complimentary used providing detailed identification of the involved paint materials..
Making a Difference
In the context of this project, a methodology for the automatic analysis of large scale spectral imaging data was developed. Moreover, for the first time, a total non-invasive and in situ examination of various degraded paint layers was performed, revealing their original composition. The scientific examination of the murals provided very important information about the history of cave 465, placing its dating in the period between late 12th to the 13th century.
Co-Investigator: Professor Su Bomin (Dunhuang Academy)
Research Fellows: Dr Sammy Cheung (Nottingham Trent University)
Shui Biwen (Dunhuang Academy)
Zhang Wenyuan (Dunhuang Academy)
Yu Zongren (Dunhuang Academy)
Research Assistant: Rebecca Lange (Nottingham Trent University)
Andrei Lucian (Nottingham Trent University)
Research Students: Sotiria Kogou (PhD, Nottingham Trent University)
Alex Hogg (MSci, Nottingham Trent University)
Stuart Christian (BSc, Nottingham Trent University)