Conservators struggle to preserve true original colors of China’s Terracotta Warriors

By Southern Weekly - Global Times Source:Global Times Published: 2017/10/10 19:01:29

Two-millennia-old Terracotta Warriors immediately lost most of their original colors the moment they were unearthed

Modern science and technology are now able to preserve the true colors of the remaining buried statues

A new online museum allows viewers a panoramic, 20-billion-pixel image of the ancient mausoleum

Pieces of Terracotta Warriors in a pit of the First Qin Emperor's Mausoleum in Xi'an, Shaanxi Province. Photo: VCG

In August, a digital museum of the First Qin Emperor's Mausoleum was officially launched with the help of Internet technology.

Thanks to the panoramic, 20-billion-pixel image, users can now view China's iconic Terracotta Warriors up close and personal to view the true ancient colors that remain on some of the figures.

Pretty much every tourist and visitor to the First Qin Emperor's Mausoleum (aka The Terracotta Army) in Lintong county, Xi'an, Shaanxi Province, can't help but be amazed by their grandeur. However, few people have had the luxury to see their true, two-millennia-old colors except archaeologists, experts and historians granted special access into the dig site.

Forty-three years ago, when Chinese archaeologists carefully removed the yellow earth away with shovels, brushes and cotton swabs, a mysterious underground army interred for more than 2,000 years surfaced, which became one of the most shocking archaeological discoveries of all time.

An array of clay warriors, with each and every figure differing in facial features and expressions, clothing, hairstyle, gestures and colors (ranging from scarlet, purple, pink and pale green to lilac, light blue, orange, black, and white) solemnly stood in the pits as if they were still guarding the first ever Empire in imperial China.

However, their 2,000-year-old Chinese colors, once exposed to sunlight and modern air, lasted for just a few minutes or even only 15 seconds. The pigments immediately dehydrated, curled up, flaked off and were gone.

Now, with advanced technology, Chinese and scientists and their foreign counterparts are able to preserve the true colors of clay warriors that have not yet been unearthed.

A terracotta warrior with his original colors is extremely rare to see. Photo: VCG

A riot of colors

On March 29, 1974, farmers digging a well in the village of Xiyang discovered some strange fragments of clay sculpted in the human form. Three months later, archeologists dug their first probes, which led to the staggering find.

The unexpected scene of these time-travel Terracotta Warriors, the rich historical heritage as well as the fleeting moments of their colorful beauty, all left archeologists with a lasting impression.

"Indeed, every warrior and horse figure was painted, but after more than 2,000 years the pigments were so old they began to change just 15 seconds after they were unearthed," said Xia Yin, researcher and director of Relics Protection Department at First Qin Emperor's Mausoleum Museum.

An academic report published in 1988 mentions the fact that the Terracotta Warriors were actually painted many times over.

Yuan Zhongyi, the then-head of the archeological team and "the father of the Terracotta Warriors," knows everything about the 2,000 figures that have been unearthed after many decades of excavation, observation, research and analysis.

"I have looked at all of the figures and made the excavation reports. I know their body shapes, clothing, hairstyles, shoes and the color when they were unearthed," says Yuan. "If we could go backwards in time, we would be able to see how colorful these figures were: scarlet, crimson, purple, pink … just to name a few."

Yuan explained that the clay warriors and horses were buried for over 2,000 years, so their color coating was already aging and peeling. Before the finish, the workers would brush a layer of lacquer to the figures to bond and highlight the pigments.

"The lacquer will be curled up and flaked off because of dehydration when being exposed to air, therefore we have to be exceptionally attentive with this. We use small tools such as bamboo sticks, scalpels, tweezers and cotton swabs in our work. This is a very sophisticated work that allows zero carelessness," Yuan added.

Today, Yuan is retired, but from time to time he has been invited back to the site where he spent most of his life excavating, together with younger archeologists, with an expectation of showing the true colors of Terracotta Warriors to the world.

Faded wonders

In First Qin Emperor's Mausoleum Museum, pit 1, at 260 square kilometers, is the largest and most impressive. It yields over 1,000 warriors and horses, all facing east in a rectangular array in solemn ash black, which is the color that most people know about the Qin Dynasty (221BC-206BC) and see in their pictures.

For archeologists, the excavation and preservation of the Terracotta Warriors are the two major problems. Changes in the environment are the main cause of the rapid color fading of figures while their preservation is confronted with micro-organisms and soluble salt.

Mold spores that exist extensively in the air and earth grow rapidly when temperatures and humidity are appropriate. Some mold growth can secrete pigments and produce acid or other harmful substances, deposited on the surface of clay figures, causing damages to the treasure relics.

Meanwhile, a layer of frosty soluble salt is congealed on the clay surface, leading to irreversible damage. A slight change in temperature and humidity would result in the repeated coagulation and dissolution of the soluble salt, enlarging the interspace in the sculpture and lowering their strength. Even a gentle touch will cause the surface to flake like a crispy biscuit.

"Environmental change, micro-organisms and soluble salt are what archeologists have identified as culprits to the discoloring of Terracotta Warriors," Xia said. "The temperature and humidity underground function as the shield of the figures' colors. Once unearthed, the surface quickly dehydrated and flaked off, which is truly regrettable. When we first discovered the Terracotta Warriors, we were not able to preserve the colors of the figures at that time."

Power of science and technology

Since the 1980s, Chinese and foreign scientists have carried out collaborative research on preservation of the Terracotta Warriors and their original colors. Breakthroughs have been made.

According to the president of the First Qin Emperor's Mausoleum Museum, Hou Ningbin, Chinese researchers have worked with experts from the Bavarian State Conservation Office in Germany since 1990s and have found a method to treat the surface with an emulsion of polyurethane and polyethylene glycol.

The preservative, known as PEG, helps save the figures' colors. During the recent excavation, archeologists sprayed the exposed parts with PEG the moment a painted figure was unearthed, then wrapped it with a plastic film to keep the humidity. The most colorful pieces were moved together with the surrounding earth to an on-site lab for further treatment.

The museum also established five special labs including a scanning electron microscope lab, a microbiology lab, a microscopic analysis lab, a colored cultural relics preservation lab and a comprehensive restoration lab. To everyone's delight, the modern techniques for preserving ancient colors have proved to be working.

"The new color preservation technique can help keep the original colors for at least 10 years," says Xia.

With the rapid development of modern science and technology, they are able to keep the Terracotta Warrior's true colors. With the deepening of research, experts also found that the Qin people had very sophisticated methods of utilizing colors. But there are still unsolved mysteries.

Unsolved mysteries

According to The Basic Annals of First Qin Emperor in Shiji, after the First Emperor's annexation of the six kingdoms following protracted wars, the color black was believed to be the most exalted color.

According to statistics, Terracotta Warriors are pale green, red, crimson, pink, sky blue, white, ochre and other colors, from which four colors - green, red, pink purple and sky blue - are the most popular. Does this finding contradict the record of "the Qin exalted black"?

"Colors are advocated differently in different dynasties in Chinese history. Color usage is related to folklore and culture. Some say that Qin advocated black, but the Terracotta Warriors show that Qin actually might have advocated many colors," Hou said.

"More types of colors and more vivid colors are used on the generals; the regular warriors have few colors and sometimes only show a simple paint, showing the concept of 'class' during the Qin Dynasty," he added.

"We divided the Terracotta Warriors into four levels. There are only nine generals, and their use of color is very complex and extremely delicate," Hou said. For intermediate and lower-ranking military officer figures and commonplace soldiers' figures, the use of color is relatively simple.

A kneeling figure, that has relatively good preservation of color, reflects that the Terracotta Warriors had very colorful clothes: he is clad in a pale green long jacket, ochre armor and the armor covered with red belts and white nails, with lower body in blue pants and purple gaiters.

Yuan believes there were both exalted colors and popular colors in ancient clothing. Exalted colors reflected the characteristics of the era and politics, with black used for a sacrifice, daily meetings and other national events while popular colors were used for daily cloths among the public.

"The colors of the Terracotta Warriors fully display the liveliness of the Qin people. It is definitely not that everyone wore black just because Qin exalted black, neither did they show sadness or low spirit," says Yuan.

"We have only excavated 1 percent of the total mausoleum. Since our technological methods are limited, with many unpredictable factors, we'd rather keep them buried," Hou said.

"It will take hundreds of years or even longer to fully reveal those colorful mysteries to the public," he said.

Southern Weekly - Global Times

Newspaper headline: A vivid history

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