Zhang worked with his two sons and his students to number the caves and begin to reproduce the murals. He also hired five lama thangka painters from the Ta'er Monastery in Qinghai province, who helped prepare special painting materials and mineral pigments, so that the recreations would retain as much of the glory of the originals as possible.
Chang Shana says Zhang asked his team to strictly follow the outlines of the patterns and figures, while he concentrated on trying to restore faded or oxidized colors, such as dark brown areas that needed to be returned to their original red pigment.
After copying murals from the caves in the Mogao Caves, they turned their attentions to recreating murals in Yulin located in an even more remote area, seizing every minute before they ran out of the supplies.
Zhang and his team often worked in the caves for 14 hours a day. At night they had to work holding a candle in one hand while they painted with the other.
Their sleeping quarters were often invaded by scorpions and they woke to the howls of wolves outside on occasion.
