Inching their cameras along a rail inside the chamber, specialists use powerful flashes to light up paintings of female Buddhist spirits drawn more than 1,400 years ago.
One click after another illuminates colorful scenes of hunters, Buddhas, flying deities, Bodhisattvas and caravanserais painted on the walls of the Mogao Caves in northwest China, considered the epitome of Buddhist art — and now in existential danger.
From the fourth century onwards, the 492 largely hand-dug caves near Dunhuang, a desert oasis and crossroads on the Silk Road, acted as a depository for Buddhist art for about a millennium.
UNESCO says the World Heritage Site is “the largest, most richly endowed and longest-used treasure house of Buddhist art in the world.”
“Dunhuang is where Chinese, Greek and Roman, Islamic and Indian arts meet,” said Mimi Gates, a former director of the Seattle Art Museum who is helping to preserve the caves, and stepmother to Microsoft founder Bill Gates.
However, their unique appeal is the very thing that is putting them under threat, with every visitor’s entrance, body and breathing altering the delicate environmental balance inside the chambers.
The remote site in Gansu Province saw 800,000 visitors last year, up 20 percent in a year. The recommended daily maximum is 3,000, but as many as 18,000 arrived on one public holiday in October last year.
The digitization project — which has been running for decades — is part of the solution, a grand project to transform the way visitors are received and cut the time they spend inside, even as numbers rise.
It is an immense task. The paintings cover 45,000m2 — if set in a single mural 3m high, it would stretch for 15km.
Thousands of images are taken of each chamber, using specialized lights to avoid damage, and then laboriously computer-processed to create a precise cyberreplica.
“Digitizing the caves is very difficult,” Dunhuang Academy director-general Wang Xudong (王旭東) said. “We began in the 1990s, but at the time, it was a failure. We continued in the year 2000 thanks to technological advances.”
The key challenge is capturing the freshness of the colors, particularly natural pigments, such as vermilion and malachite green, as well as any areas that are not flat, such as corners and sculptures.
Once the new system goes into effect next year, visitors will be overseen as soon as they reach the airport — essentially the only convenient entry point for Dunhuang — and have to stick to a tightly controlled sightseeing circuit.
In a domed theater currently under construction, they will view high-definition images of the inside of the chambers, before taking a glimpse inside the real thing — but only for a limited time.
Long after Dunhuang’s heyday, the Silk Road eventually fell into disuse and it was largely forgotten by the outside world, with most of the caves abandoned.
In 1907, Hungarian-British archeologist Aurel Stein led an expedition to the area and paid to remove large numbers of manuscripts, paintings and textiles. A French mission under Paul Pelliot acquired thousands of items the following year, and Japanese and Russian expeditions soon followed in their footsteps.
However, the latest collaboration will preserve Dunhuang for future generations, say those involved, and make the masterpieces available to academics and amateurs around the world online.