German restorers are using traditional Vietnamese methods to restore the facade of the Imperial Palace in Hue. Restoration work is currently being carried out on Buu Thanh Gate and screens around King Tu Duc's tomb.

The Germany foreign ministry has commissioned experts from the German Conservation, Restoration and Education Project (GCREP) to renovate six murals dating from the Nguyen Dynasty in the lobby of An Dinh Palace.

The artwork is magnificent, but heavily damaged. Before attempting to restore the murals, team leader Andreas Teufel sent samples back to Germany for chemical analysis.

The team is using traditional mortar made from molasses, lime and sand to restore the works. Teufel said the restored parts of the palace will be indistinguishable from the original work.

"Previous restorers tried to preserve the original works but they didn't know how to do it properly and didn't have access to modern technology," she said.

"That was why relics at the site have largely been left unrestored. The work they did was far from perfect and bore little resemblance to the original. People in the past used different painting techniques. The Vietnamese restorers used modern pigments and techniques," she said. "I discovered that the original painting technique was similar to that used in Italy."

The German restorers have used traditional pigments, which are applied to the wet mortar. The colour will be fixed when the mortar dries. Bacteria will grow on the walls during the drying process, which helps to make the artwork more durable.

The restoration work is in keeping with UNESCO's 1964 Charter.

According to Phan Thanh Hai, Vice Director of the Centre for Restoration of Hue Relics, the techniques used to restore the palace will be applied to other sites.