The Manual of Calligraphy and Painting (Shi Zhu Zhai Shu Hua Pu) from 1633 is the earliest Chinese book printed using the technique known as polychrome xylography (douban) in which multiple printing blocks coated with colored inks are applied to paper to produce a watercolor painting effect. But the book’s stunning images of birds, plants, flowers, fruit stones, and accompanying poems have long been clamped shut, too fragile to be opened.

Some pages in that 138-pages book (source: Cambridge)

Created by Hu Zhengyan and his Ten Bamboo Studio in Nanjing, the book includes 138 paintings and sketches and accompanying texts by 50 different artists and calligraphers and is “estimated to be worth millions on the open market,” notes the release. While the book has been reprinted many times, complete sets of early editions in the original butterfly binding are extremely rare. “The binding is so fragile, and the manual so delicate, that until it was digitized, we have never been able to let anyone look through it or study it—despite its undoubted importance to scholars,” Aylmer said.