The huge piece, marked by exquisite workmanship and the glowing colors of natural pigments, demonstrates the peak reached by Chinese lacquerware over 2,000 years ago.
However, when it was excavated in 2000, it was in a horrible condition. "The bird's beaks, wings and legs were either broken or rotten, and the drum could not stand on its own. It was disheartening look at," Wu recalled.
The water-logged drum was extremely fragile and was at risk of irreversible damage without careful restoration.
Due to the difficulty of safely removing the moisture, many pieces of excavated lacquerware were kept under water for decades, until Wu made a significant breakthrough.
He found that applying glyoxal, an organic chemical, during the dehydration process effectively preserved the original shape and color of the lacquerware.
The technique led the State Administration of Cultural Heritage to entrust the center with the restoration and preservation of 400 pieces of lacquerware unearthed from Mawangdui Han tombs in 1970s.
After moisture has been removed, experts apply natural pigments to restore the lacquerware's original colors.
This step is time consuming as six coats of paint are required, with each coat needing at least one week to dry before next can be added.
It took five years for the team to completely restore the drum.
More than 6,000 pieces of lacquerware unearthed across China have now been dried out and repaired using the scientist's technique.
SILK
Wu's team has also been exploring new techniques to restore ancient silk, an extremely delicate and complex task.
Silk does not preserve well and many pieces unearthed from tombs have already started to decompose or disintegrate. For example, unearthed silks from in the Warring States Period (475-221 B.C.) have usually started to rot after being buried for more than 2,000 years. Even if they survive excavation, the fragile textiles can easily be ruined, similar to bamboo slips.
Using unique biological technology, Wu and his colleagues have preserved with more than 500 pieces of silk, including a rare gown embroidered with birds and flowers.
In January 1982, archeologists found the gown amongst 152 pieces of silk inside a coffin unearthed from a Warring States Period tomb in Jingzhou.
In 2000, after years of research, Wu developed a technique of using microorganisms to eat away at hazardous substances on the textiles, such as mildew and salt crystals.
The State Administration of Cultural Heritage recognized the technique as "revolutionary" and "world-leading," honoring it with a national prize for innovation in cultural relic preservation in 2005.
The gown has been reinforced to the point where it is now foldable. The next step is to mend the damaged sections, before it can be put on display.
"The piece is so precious that we must be scrupulous about its repairs," said Wu. "Chemicals cannot be used. We're testing Pu'er tea as a dye."
In terms of restoration, every item presents a different set of circumstances, and a new task poses a unique challenge," Wu said.
