How Tech Lights Up Longmen Grottoes

LUOYANG, China, Aug. 24, 2026 /PRNewswire/ -- A report from Science and Technology Daily: 

"Among the four suburbs of Luoyang, the finest scenery lies at Longmen." Tang Dynasty poet Bai Juyi wrote these lines more than 1,200 years ago. Standing on the bank of the Yi River in Henan, central China, he saw the same cliffs we see today.

The Longmen Grottoes consist of 2,345 caves and niches housing nearly 110,000 Buddhist statues, and more than 2,800 inscribed steles. They have stood here for over 1,500 years. The chisels that carved them fell silent long ago, but the stone remembers. In November 2000, the Longmen Grottoes were inscribed on the UNESCO World Heritage List. "The grottoes and niches of Longmen," the committee wrote, "represent the high point of Chinese stone carving."

That judgment stands, but standing is not the same as enduring. Water seeps, wind erodes, and the stone has also suffered at human hands. In the past, conservation used to mean intervening after damage. Today, it means anticipating it and preventing it. Technology has made that shift possible. It answers a fundamental question: How do you keep "alive" something that is older than any living memory and made of stone?

This special edition follows Camilla Quaranta, an Italian student at Henan University, and Li Xiawei, a young guide at Longmen, as they discover the technologies reshaping how the site is conserved and experienced today.

Keeping Cultural Heritage Forever Young

In AD 500, after the Northern Wei Dynasty's relocation of its capital to Luoyang, construction began on a massive state project in the Yique Mountains located south of Luoyang. This was the Binyang Middle Cave, the only royal grotto at Longmen whose construction process is explicitly chronicled in official historical records.

More than 15 centuries later, an Italian student stood before it. Camilla Quaranta grew up in Milan, where she often visited museums and old churches with her family. Those early encounters with Roman relics and Renaissance art sparked a lifelong love of history. Now studying at Henan University, she came to China with a particular curiosity: to see for herself how an Eastern civilization, so different from her own, has endured over time. Longmen Grottoes was one of her stops.

Her friend Li Xiawei, a young guide at the grottoes, accompanied her into the cave. "Welcome to wonderland," Li said.

They looked up at the dome. A giant double-petal lotus has been "blooming" there for over 1,500 years. Around it people can see a blur of celestial musicians, whose colors and outlines have long faded.

"What did it look like when it was first built?" Camilla wondered quietly. In the past, one could only imagine. Today, using a combination of advanced technologies, the research team at the Longmen Grottoes Academy has digitally recreated the original appearance of the lotus caisson.

"We do not have to time travel," Li said. "Now, through digital technology, everyone can see what they originally looked like."

Moving south, they arrived at the Ten Thousand Buddhas Cave, a Tang Dynasty cave named for the 15,000 small seated Buddhas carved into its walls. On the south wall of the front chamber stands a damaged statue of Guanyin, known in Sanskrit as Avalokitesvara. The head and arms of the statue are missing.

Li showed Camilla an old photograph of the undamaged Guanyin. Based on that, the team created a digital version in which the face, robe and decorative ribbons have been restored, reflecting the original appearance.

"Will I ever see a statue like that again?" Camilla asked. "I think so. In the digital world," Li replied. Camilla wanted to understand how this was done. Li took her to the Academy, where they met Zhang Guofeng, deputy head of the Exhibition and Digital Section.

Zhang told them the Academy's digital work began 20 years ago with the "Longmen Grottoes 3D Digitalization Project." In 2021, the team launched a new phase, conducting high-precision data collection for representative caves to create comprehensive digital records. Unlike earlier methods like drawing, molding, and black-and-white photography, the latest 3D scanning can achieve millimeter-level accuracy without touching the artifacts.

For the Guanyin statue, the first step in virtual restoration was finding evidence, Zhang said. Drawing on historical photographs, academic research, 3D digital technology, color analysis, and traditional sculptural knowledge, the team virtually restored the statue and its original colors.

"Virtual restoration isn't about making it 'look complete,'" Zhang said. "It's about getting as close as possible to what it originally looked like. That distinction matters." When Camilla asked about the "authenticity" of digital restoration, Zhang said, "Digital restoration is more a form of witnessing, more about the process. Cultural relics are cultural relics. Virtual restoration simply allows people to see what these relics looked like before they were damaged. It is a form of conjecture and verification."

For Zhang and his colleagues, the goal of digital restoration goes beyond freezing a moment in time. It is about keeping the artifacts "alive," preserving their information before further decay and carrying their presence beyond the cave walls, into spaces where stone cannot travel.

Today, through AR technology visitors to Longmen Grottoes can view the figures as they originally appeared by pointing their smartphones at the damaged statues.

"This is just the beginning," Camilla said, looking at the restored image on the screen. "What moves me most is seeing the past come back and knowing that these grottoes can now travel to classrooms, museums, and screens anywhere in the world. They no longer belong only to this mountain. They belong to anyone who wants to see them."

SOURCE Science and Technology Daily