Chinese experts have adopted digital technologies to collect data and "replicate" 1,500-year-old Yungang grottoes through 3D printing, as part of the efforts to "perpetuate" Buddhist statues in the caves.

Tourists visit the Yungang Grottoes in Datong, North China's Shanxi Province, April 6, 2019. （People's Daily Online/Ren Xuefeng)

The seemingly insignificant deformation, such as crumbling in the grottoes, is considerable over the course of 10 years, 100 years and 1,000 years.

Although the means of cultural relic protection is becoming more and more abundant, the degradation of the grottoes cannot be completely stopped in accordance with the laws of nature.

At 7 p.m. on Oct. 20, Pan Peng, one of the experts, walked into the eaves of cave No.11 in Yungang grottoes with his colleagues and a flashlight. The eaves of the grottoes are a three-story antique wooden building, which is close to the outside of the grottoes, and is equivalent to a shell in order to protect them. Equipment can also be installed in the "shell" to adjust the dryness and humidity of the grottoes.

A shadowless lamp and a shed flash light illuminated the dark grottoes. Li Zehua and Wang Chao, Pan Peng's colleagues, took SLR cameras to photograph the last remaining part of the east wall, which casts a huge shadow on the inner wall.

In order to distribute the light evenly, the camera was equipped with a special circular LED supplementary light. In the work preparation area in the eaves of the cave, there were more than a dozen strobe and shadowless lights, with black chargers for all kinds of equipment spread across the floor.

This is part of the process where the experts duplicate the caves of the Yungang grottoes.

The digital collection of cave No. 11 was launched after the National Day holiday this year. Just a few days ago, the work on the first floor of the top of the cave was completed, and the first layer of wood was immediately removed.

Currently the work focuses on the second floor from top to bottom.

The world's first mobile 3D-printed 1:1 replica cave of the Yungang Grottoes, cave No. 12, also known as the Music Cave, made its debut on June 12 at the Museum of Art and Archaeology in East China's Zhejiang province, which opened to global visitors both offline and online.

After the exhibition in Hangzhou, capital of Zhejiang, the replica of the Music Cave will start a global tour.