Of the renovation efforts, the most complicated one will be to restore the colourful paintings under the eaves, said conservationist Li.

Paintings were created directly on the wooden walls and on both the outside and inside of the eaves. While those on the inside retain their original look, those on the outside were covered with some coarse ones during a maintenance project in 1959.

Jin said researchers at the Palace Museum have found documents describing the ancient paintings on the outside walls. Conservationists are going to remove the paintings of 1959 and put up new ones that will be created on the basis of the documents and the old paintings on the inside.

The whole process will involve 13 procedures as outlined in the millennia-old documents.

The first step will involve getting rid of the 1959 paintings. This requires special care to ensure that the wooden walls are not damaged.

The next step will involve mixing the powder of bricks with the blood of pigs, applying this mixture to the part of the wooden walls to be painted upon, and then burying a thin layer of flax cloth into it.

The mixture will turn black when it dries up. After polishing its surface, conservationists will apply a layer of oil made from a special kind of tree.

Then the chief artisan will create drafts of the paintings on pieces of paper and make small holes with needles along the lines drawn on these drafts.

The paper will then be placed on the mixture of brick powder and blood on the walls and cement plastered onto the paper. This will leave white traces on the black mixture through holes in the paper. It is according to these traces that artisans will paint and fill in the colours.

"The traditional procedure to finish a painting on the walls can never be replaced by modern technologies," said Li.

"Fortunately, we have families in our renovation team who have worked for hundreds of years on these palaces. The skills that our ancestors used in building the palace have almost all been handed down," he said.

Traditional skills will also be used to make the golden glazed tiles. More than 60 per cent of the 10,000 tiles on the roof are worn out, said Zhang Kegui, also a conservation expert at the Palace Museum.

Meanwhile, cutting-edge technologies will be applied where appropriate based on the draft of the renovation plan, drawn up by experts from both the Palace Museum and the Italian Ministry of Cultural Heritage.

The fallen patches of wall coverings, for example, are to be pasted back one by one with a kind of high-tech glue.

(China Daily 04/10/2006 page5)