Researchers from Tianjin University use 3D model to monitor murals and environment of Dunhuang Grottoes. Source: GUANGMING

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Huang Jinhai, a professor from the School of Life Sciences at Tianjin University, has been leading students to extract oil from various flowers. The purpose, however, is not to make perfume, but to protect ancient paintings.

In an experiment, Huang accidentally found that clove oil could resist a fungus that grows on paper products and woodworks that have been stored for a long time. This fungus is the direct cause of the mildew that destroys ancient calligraphy works, paintings and wooden relics. “Students have gathered fungi from Tianjin Museum’s collection and identified six varieties. We are trying to best match the genus of clove with the variety of fungus. Also, we want to know the relationship between amount and effect,” Huang said. “Now, we can apply clove oil to the paper and put the paper with cultural relics. The oil will volatilize slowly and its volatility will prevent fungi. In this way, the storage environment has a pleasant smell and the cultural relics are not damaged.”

The “Snow and Forest Map” is one of the few surviving masterpieces by Fan Kuan, a painter of the Northern Song Dynasty. This renowned water and ink painting on silk scroll is now preserved in the Tianjin Museum, the earliest museum of its kind both run by governments and supported by the public.

Tianjin has a history of about 600 years; there are not many relics unearthed there. “Tianjin Museum, however, has a wide range of exhibitions most of which are relics donated by private collectors. These relics, particularly silk products, ancient calligraphy works and paintings on paper or silk scroll, are more difficult to protect than those kept in a stable environment for years, as they were created hundreds of years ago and have circulated among multiple collectors,” said Chen Zhuo, curator of the Tianjin Museum.

To Chen’s delight, the flower oil method for relics protection can help preserve the Snow and Forest Map for a longer time, so that future generations can appreciate the long-standing charm of ancient arts.

The construction of Yingxian Wooden Pagoda, also known as Sakyamuni Pagoda of Fogong Temple, started in 1056 in Shuozhou, Shanxi Province. It took craftsmen 140 years to complete the 20-story wooden building. As the oldest existent fully wooden pagoda still standing in China, it is credited as a museum for dougong, a unique structural element of interlocking wooden brackets. Restoring the pagoda has been a long and difficult process.

How can a nail-less building with 3,000 tons of wooden components stay intact after suffering several major earthquakes, lightning strikes and shelling? Experts from Tianjin Electronic Information College and Nankai University hoped to unlock the secret through 3D modeling technology.

Zhou Enbo, director of the Research Office for Architectural Design at Tianjin Electronic Information College, said that “The repair work of Yingxian Wooden Pagoda has involved universities since its early stage, such as Taiyuan University of Technology, Tsinghua University and Nankai University. As a college, we have our own advantages. Our students have a strong ability to apply technologies. They adopt information technologies to create digital documents that lend great support to the repair work.”
 

Almost all scholars who have visited the wooden tower wanted to figure out its structure. In 1933, the renowned architect Liang Sicheng (1901-1972) measured and mapped the building, followed by many other scholars. Their efforts turned out useless. Zhou explained: “The traditional buildings in our country have no drawings. Yingxian Wooden Pagoda is all constructed by wooden joints. If you want to understand them, you have to dismantle them, but no one is confident about restoring the wooden components after dismantling them. Therefore, its overall structure has never been overhauled. Previous renovations all targeted subtle parts. As time goes by, the wooden pagoda is now tilting, making the repair more urgent.”

The teachers and students of Tianjin Electronic Information College  try to overcame this intimidating problem by constructing a 3D model. They make physical models with wood and then compare and adjust in detail. “This method does not harm the pagoda. And it has also improved in efficiency now that our team has finished modeling the building’s first floor,” Zhou said.

It is often too late for relics when people start rescue protection. The concept of preventive protection was proposed in the field of cultural relics long ago, but professionals have failed to find feasible solutions. Sun Jizhou, Zhang Jiawan and Feng Wei are professors from the Research Center for Information and Technology on Heritage Protection and Inheritance at Tianjin University. They have devoted 10 years to using modern technologies to give relics new life. This group of scientists who deal with computers every day have become guardians of cultural heritage.

“In the past, the work mainly depended on laboratory research, but the conditions of real environments are more complicated,” Zhang said, explaining that they couldn’t identify how environmental conditions affected relics due to a lack of testing methods and data. Therefore, the team invented a modeling method named relation between relics and risk sources, which was considered as a method for preventive protection. Such technology has been applied to a couple of heritage projects, such as the Dunhuang Research Institute, the Summer Palace and the Labrang Monastery.

In the collaboration with the Dunhuang Research Institute, Zhang’s team selected 11 caves and 47 monitoring sites at Dunhuang Grottoes to monitor murals and painted sculptures. They gained data by means of micro-variation sensors, image analysis and other technologies relevant to artificial intelligence. Based on the mural monitoring and data analysis from 2014 to 2016, Feng for the first time tracked the 0.1mm-level changes of murals that took place within a year. The finding is regarded by authoritative experts as a -substantive breakthrough in the field of relics protection.

“By comparing the changes before and after, we discover how murals get destroyed,” Zhang said, noting that “in the past, we only monitored the environment while turning a blind eye to the cultural relics themselves. We neglected the interactive impacts between the cultural relics and the environment.”

Today, this team of more than 20 people, with an average age of 30, is travelling across the country to preserve ancient civilization with modern information technology. Zhang hoped that more natural science researchers can join them and integrate modern science and technology with museology, so as to “bring to life the cultural relics collected in museums, the heritage present across the vast land and the characters written in ancient books.”

 

(edited by MA YUHONG)