Newly made Kaihua paper. [Photo/Tide News]

Kaihua paper, a traditional handmade paper from Kaihua county in Quzhou, Zhejiang province, is finding new applications as craftspeople and researchers revive its lost production techniques through years of work.

Prized for its fine texture, toughness, and durability, the paper was used for imperial publications and important books during the Ming and Qing (1368–1911) dynasties. Its production techniques gradually disappeared in the late Qing Dynasty.

Local craftsman Huang Hongjian began reviving the technique in 2009. A Fudan University research team joined the effort in 2015 and identified locally grown raohua (Wikstroemia canescens) as the main fibrous material for the restored paper.

The thinnest restored Kaihua paper weighs only about 2 grams per square meter. Accelerated aging tests have projected a lifespan of more than 2,800 years for samples made from raohua.

The revival is especially valuable for ancient book preservation. According to Yang Guanghui of Fudan University, about 15 million of China's roughly 50 million volumes of ancient books are undergoing accelerated aging and acidification and require restoration.

The Zhejiang Paper Industry Association recently issued a group standard for Kaihua paper, specifying technical requirements, testing methods, and inspection rules to improve quality consistency.

Producers are also testing semi-mechanized papermaking equipment and expanding raohua cultivation in preparation for standardized production.

Beyond book preservation, restored Kaihua paper has been used for Fudan University admission letters, cultural products, and even graduation certificates handmade by primary school students in Kaihua.