Dyeing vessels on display at an exhibition on the printing and dyeing craft of blue calico in Hangzhou on October 1, 2014.

Blue calico is a traditional Chinese handmade printed fabric. Dyed in indigo, it has a blue base with white patterns. Tongxiang, a city in east China’s Zhejiang Province, is well-known for printing and dyeing blue calico. The craft boasts a history of a millennium in the town with its heyday in the Tang (618-907) and Song (960-1279) dynasties. The technique was widely applied by the general public during the Ming and Qing dynasties (1368-1911).

According to historical records, during the Song and Yuan (960-1368) dynasties, streets in Tongxiang were flanked by a number of dyehouses and its rivers were dotted with boats carrying bolts of dyed cloth to be sold. Till the early period of the Republic of China, dyeing businesses still thrived there. The time-honored dyeing craft was added to the list of national intangible heritage items in 2014.

The process of dyeing involves a series of steps, including carving boards, applying paste, dyeing, scraping paste, and drying. The first major step requires craftsmen to draw motifs, normally symbols of health and good luck, on a board. The craftsmen then carve the motifs. Next, the carved board is placed on a piece of white cloth and then a specially prepared reabsorption resistant paste is applied to the interstices on the board. This paste is usually a mixture of soybean and lime. In this way motifs are printed on the cloth.

Next the cloth is submerged in the dye. The indigo dye is made from a locally grown plant, named “Lan Cao,” meaning “blue plant.” The newly dyed cloth takes on a green hue and needs some time to oxidize before turning blue. Each piece of cloth usually goes through repeated cycles of submersion in the dye. The oxidizing process in each cycle deepens the blue shade. After the dyed cloth has dried, a blade is used to scrape off the hardened paste residue from the fabric’s surface. In the final phase, the fabric is hung out to dry after a rinse in water to remove the surface color.

This fascinating dyeing skill is still sharing its wondrous tales. The Wuzhen scenic spot in Zhejiang houses two dyehouses showcasing the classic Tongxiang dyeing skill to the public. One offers a live demonstration of the technique while the other provides an opportunity for visitors to dye by themselves.