View of the Mogao Grottoes cliff face from the Gobi desert. Photo: Cecily Grzywacz.

Flying Apsaras Pharmacy in Dunhuang, China. Photo: Cecily M. Grzywacz.

The project team purchasing biological source material at the Flying Apsaras Pharmacy in Dunhuang, China. Photo: Cecily M. Grzywacz.

Freshly harvested madder root, Rubia tinctorum, donated by the Huntington Library, Art Collections, and Botanical Gardens, San Marino, California. Photo: Jan Wouters.

Jan Wouters beginning preparation of Caesalpinia sappan or su mu reference samples by grinding wood chips. Photo: Cecily Grzywacz.

Painted plaster coupon prepared at the Dunhuang Academy. Photo: Cecily Grzywacz.

Cary Stehl, Cecily Grzywacz, and Rita Gomez with a specially designed crate to transport wall painting coupons between the Dunhuang Academy and the GCI. Photo: Jan Wouters.

Cecily Grzywacz opening crate containing plaster wall painting coupons that arrived from the Dunhuang Academy in March 2007. Photo: Jan Wouters.

Cecily Grzywacz inspecting one of the painted plaster wall painting coupons. Photo: Jan Wouters.

Dyed wool, dyed silk, prepigment, and organic pigment reference samples prepared with plants known to have been used in China. Photo: Cecily Grzywacz.