Unveiling the colors of history

Techniques to revive, restore and preserve the colors of ancient times have been revealed during the first China International Trade Fair of Heritage Preservation held in Xi'an over the weekend. Advanced color conservation methods are being used to restore the famous Terracotta Warriors and other relics to their original states.

Photographs of over 10 pieces of colored kneeling archers excavated from Pit No.2 in 1999 that have been preserved with the new methods were on display as part of the exhibition.

Chinese and German experts made a breakthrough in 1997 by discovering that Polyethylene glycol 200 (PEG200) can penetrate the tiny pores of lacquer and keep color close to its original application.

"The technique, if processed in the correct way, can keep 100 percent of the original colors of the warriors. But it is a time consuming job. It usually takes four people half a year to finish the color conservation of one terracotta warrior," explained Rong Bo, an associate researcher at Emperor Qin's Terracotta Warriors and Horses Museum.

"During the first excavation in 1974 our staff had nothing to do but watch the color fall off the unearthed warriors," recalled Rong. He explained that the lacquer shrunk and cracked after the warriors were removed from the humid soil, resulting in the paint flaking off.

"What makes it so hard to conserve the color of the warriors is the lacquer layer between the outer paint and the terracotta," Rong added.

As part of the preservation trade fair, German company Scheidel also displayed their technique of stripping fake colors from antiques to reveal true colors underneath.

In the company's exhibition room, two eye-catching photos of the ZenTemple in Taipei showed bright colors and natural wood tones. The structure was built in the year 1900 and had undergone several color renovations.

Experts applied the paint-stripping technique in 2007 to reveal the temple's original color palate."The technique was modified when it was brought in Taiwan because of the different climate, humidity and temperatures," Hong Shengli, an expert in heritage protection told the Global Times. "Now with improved techniques, color stripping work is justa matter of craftsmanship," he added.

While the new technology is a breakthrough, there is still much work to be done, explained Georg Scheidel, president of Scheidel. He said that there have been several situations where the technique has not been completely successful and further research is needed. Scheidel added that the most important approach to preservation is to be as environmentally friendly as possible and to keep harm to relics at a minimum.

Rong agreed that while new techniques are helping to revive history and that color preservation of some of the warriors has been successful, replacing lost color is still a problem."The layer of paint [on the warriors] is like the clothes you wear.
When they are rumpled, we know how to iron them and keep them fresh. When they come off and are glued to other objects, it is hard to put them back on," Rong explained.

He added that the warriors were colored before they were buried however various incidents over the course of time had damaged them and could not simply not be undone. "Inadequate preservation methods in excavation is only one factor for the disappearance of the paint on the warriors. Pit No.1 was once set on fire, only a small number of warriors survived with painted colors partially intact."

Source: Global Times