How Science Is Keeping Angkor Wat’s Beauty Queens Alive

It is the largest printed photograph ever: The image of one of Angkor Wat’s famous bas-reliefs is 1.25 meters tall and 62 meters long.

The photo, entered in the Guinness Book of World Records as the largest in the world, is part of a German documentation and restoration project on Cambodia’s most famous medieval temple.

With techniques drawn from engineering and chemistry, the Germans are employing science to rescue art-and achieving impressive results.

The project’s efforts earned another world record for largest photographic negative-some of the negatives are 70 mm by 2,450 mm-that is, nearly 2.5 meters long.

Even the smaller prints of these finely detailed, grayish-green pictures-copies measuring about 10 centimeters by 1 meter are for sale for $50 behind the temple-provide a totally new perspective on the beautiful carvings.

Viewing the murals, which actually measure about 2.2 meters by 94 meters, in person is a wonderful experience. But since they are housed in narrow galleries, it’s impossible to step back and get a sense of the whole.

Viewing the photos gives you an instant comprehension of just how unified the bas-reliefs are-their scale, their detail, their organization. Their long, narrow shape gives them a sense of both evolving narrative and simultaneity.

The panoramic photos are just one example of the up-to-the-minute technology the Germans are using on the Angkor Wat carvings.

They were taken using a technique called “slit-scan” photography, specially adapted for this purpose. This involves a panoramic camera with a tall, narrow aperture-a slit-mounted on a trolley that rolls at a steady pace down rails that run the length of the gallery. The trolley also holds a giant light source near the bas-reliefs.

To achieve the photos’ sharpness and evenness, all the photos were taken at night. A computer system propelled the trolley smoothly along the track, and in about 35 minutes, an entire 94-meter-long carving was captured on a single length of film.

The Germans are using other novel techniques as well. Their major project is an effort to restore Angkor Wat’s nearly 1,850 apsaras, the famous carvings of heavenly, bare-chested women that encrust the temple.

Since most of these carvings are on the outside of the temple, they are exposed to the elements, making them especially vulnerable to deterioration, according to Dr Hans Leisen, a professor at the University of Applied Sciences in Cologne, Germany, and the director of the German Apsara Conservation Project.

Two main factors cause the stone to decay-the weather and the stone itself. Sandstone is “loose, porous and very absorbent,” he said. Composed of quartz and feldspar grains held together by clay, the stone can’t withstand the repeated wetting and drying imposed by Cambodia’s climate.

The result, Leisen said, is a phenomenon called “scaling”-the exterior layer of the stone peels away from its foundation and may fall off.

“For a long time you can’t see this decay because it’s on the inside,” Leisen said. “Usually, by the time you recognize it, it’s too late.”

The German researchers examined all the apsaras and rated them from 1 (excellent condition) to 6 (nearly lost). About 20 percent of the figures got an alarming 5 or 6 rating. In some cases, a detaching scale layer could be seen, poised to tumble.

“We took emergency measures in these cases,” Leisen said-using string or casts to hold scales into place.

Next, the researchers had to figure out how to go about fixing the weather-battered nymphs. This, they knew, would be a special challenge: “We are trying to restore the stones as they are”-damaged and unstable- “to their condition before they were weathered,” Leisen said.

In restoration circles these days, the buzzword is “reversible”-any modern work done on ancient monuments should not leave permanent traces that can’t be undone.

“There is no reversible intervention on porous materials like sandstone,” Leisen said. To get as close as possible to the ideal of reversibility, “We tried to find materials that are compatible with sandstone, that behave like sandstone.”

The solution they found reeks more of the chemist’s lab than the sculptor’s studio. Ethyl silicate, a liquid, is injected into the stone, where it reacts with water and hardens to produce silicon dioxide, a compound similar to quartz. The silicon dioxide binds the grains of the sandstone together, re-attaching the scales to the stone.

A 16th- or 17th-century Cambodian poet once wrote of the apsaras, “These millions of gracious figures, filling you with such emotion that the eye is never wearied, the soul is renewed, and the heart never sated! They were never carved by the hands of men! They were created by Gods-living, lovely, breathing women!”

Now, as the hands of men give new life to the apsaras, their serene smiles and elegantly posed hands still leap from the walls of Angkor Wat-beckoning the centuries to come.

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