A luxury high-tech display case will be installed in the Forbidden City on September 15 for the first-ever exhibition of a Chinese masterpiece, Qingming Shanghe Tu from October 10.

Qingming Shanghe Tu, or Riverside Scene at the Qingming Festival, is a masterpiece by Zhang Zeduan of the Northern Song Dynasty (960-1127).

The large silk scroll is about 16 meters long, and brings to life 648 human figures, 96 animals and 122 houses.

"It has never been exhibited in its entirety before because of the lack of a suitable and safe display case," Li Guomeng, a staff member at the Palace Museum, said.

However, the painting will make its full size debut when the museum celebrates its 80th anniversary in October, thanks to a colossal high-tech display case made by scientists from the Beijing University of Technology.

Sixteen meters long and weighing more than five tons, the display case is the largest and heaviest in the world. It was built at a cost of 2 million yuan (US$247,000).

It employs an energy storage technology that keeps interior temperatures between 16 and 20 degrees Celsius.

"We use a type of material that accumulates energy in the day and releases it at night," said Professor Ma Chongfang, the leading scientist of the university's College of Environmental and Energy Engineering.

And instead of water, an inert liquid called fluorocarbon fills the two layers of glass that surround the painting. This regulates the temperature and provides better security.

"If the case breaks, the liquid will not damage the painting. However, water would damage it," Ma explained, adding that the heavy glass is bullet-proof.

It is the first time in the world that fluorocarbon, usually used in cooling technology, has been applied to a display case.

"The case will be filled with nitrogen, with the oxygen content under 0.5 percent, below the prescribed US standard of 2 percent," Ma added.

All the effort is a bid to negate the unfavorable conditions of the Forbidden City.

"Unlike most museums, like the Louvre for example, which are well equipped with advanced technologies, the Forbidden City is made of wood. This means there's good ventilation, but it's not ideal for the preservation of old things," Ma said.

An automated lighting facility and a heat pump, which can reduce energy consumption by 60 percent, will also be used.

The museum's Li said the painting will be displayed in the high-tech case until the end of the year, perhaps longer.

"I think it's better for the painting to stay in the custom-tailored case permanently," he added.

(China Daily September 13, 2005)