In the old days, every rural household in Zhejiang and Jiangsu would weave and dye cloth. The clothes worn by the older generation, the furoshiki used daily, and even the dowries of their daughters are all blue calico printed and dyed by their own textiles. Curtains, headscarves, aprons, bags, tents, etc. can all be made with it. Blue calico seems to be a special fabric for the working people of the Han nationality.

The main producing area of ??blue calico in Jiangsu and Zhejiang is in the Nantong area of ??Jiangsu. Since the Ming and Qing Dynasties, Nantong, Jiangsu Province has been China's cotton textile base. The blue printed cloths printed there are popular all over the world. Nantong's blue printed cloth printing and dyeing techniques continue to this day. Daily necessities are made by hand spinning, hand weaving and hand dyeing. The printing and dyeing patterns are based on plants. Flowers and animal patterns are the main ones, but there are also simple geometric figures. It is deeply loved by the masses for its characteristics of being stain-resistant and wear-resistant, strong and durable, and having auspicious patterns. It is famous for its harmonious blue and white beauty, full of rich local flavor, natural and fresh. Nantong is a key area in the country for the research, development and production of folk blue calico, and is known as the hometown of blue calico in China.

The use of indigo dyeing by Han people can be traced back to the Spring and Autumn Period and the Warring States Period. Xunzi, a great thinker in the late Warring States period, witnessed the pigment transformation process of green "indigo" and the dyeing process from yellow to green and from green to blue. , the process of turning green again, the green comes out, is derived from blue, and the exclamation that green is better than blue has become an eternal saying describing the superiority of future generations over their predecessors.

It has been more than a thousand years since indigo developed into the indigo dyeing technique. The "Essential Art of Qi Min - Planting Blue" written by Jia Sixie of the Northern Wei Dynasty specifically describes the method of extracting blue lake from blue grass: Make a pit in the middle of July, make a pit with a hundred bundles, make wheat straw mud, and make it five inches deep. Cover the four walls with thatch. The cutlery was placed upside down in the pit, put into the water, and suppressed with wood and rocks to order it to be submerged. One night when it's hot, another night when it's cold, drain it, put the juice in an urn, put it in a ten-stone urn, put a bucket of five liters of lime on it, throw it down hastily, and stop it after eating. Clear and purge the water, make a small pit, and store the blue water in the pit. The time is like strong porridge, but it still comes out of the urn, and the blue lake is ready. This is the earliest record of the blue lake making process in the world.

Nantong has simple folk customs since ancient times. It is near the river and the sea, and is warm and humid. It is especially suitable for the growth of cotton. Cotton planting is very common in local rural areas. In addition, the local Han folk textile technology is very developed, especially the Zodiac of the Yuan Dynasty. After learning the textile technology of the Li people, Po returned to his hometown of Songjiang, Jiangsu Province, introduced the Li textile tools and improved them, which promoted the development of the cotton spinning industry in Songjiang and Nantong areas. After the Song and Yuan Dynasties, every household had wooden spinning wheels and looms, and the sound of cloth looms could be heard in every household. There were weavers in every household, and Nantong became a famous textile town. Cotton cloth has become quite popular among Han people.

With the development of cotton spinning handicraft industry, bluegrass was planted in large quantities and dyeing workshops increased one after another. Nantong is warm and humid, especially suitable for the growth of bluegrass. The dye of blue calico is based on indigo grass. Indigo grass is mainly divided into four types according to the characteristics of its family and growth environment, namely polygonum indigo, mountain indigo, wood indigo and woad. Jiangsu is famous for its rich production of Polygonum indica. During the Ming and Qing Dynasties, Nantong's blue-print cloth dyeing and weaving workshops had developed into large-scale markets. According to the "Nantong County Chronicle" of the Ming Dynasty, there were as many as 19 hand-dyed workshops registered in the Dyeing and Weaving Bureau.

People's demands for daily necessities are constantly increasing. The original simple and rough graphics can no longer meet people's aesthetic and life needs. Folk artists boldly absorb traditional art patterns such as paper-cutting, embroidery, and wood carving, and continue to enrich them. Pattern of dyed and woven blue calico. At the same time, with the development of the oil-made umbrella industry, tung oil paper is used to engrave patterns, which saves labor and time. After oiling, the patterns are water-resistant and scratch-resistant, have a long service life, and have richer patterns. Make its technology more mature. The wide application of folk blue printed cloth has promoted the rapid development of the printing team. "Print workers" are also called "flower workers". They only print and paste, but do not dye, and provide farmers with various forms of patterns. This kind of "printing burden" is also called "bald printing" in Jiangnan. They walk through streets and alleys and villages. One end of the burden is loaded with soybeans and lime powder, and the other end is equipped with scraping tools and patterns. Customers can choose Pattern processing, they constantly change patterns in order to achieve a prosperous business. At the end of the Qing Dynasty, there were still nearly a hundred people in the stamp dan team in Nantong area. Farmers send the scraped gray cloth to nearby dyeing houses, or they make indigo dyeing themselves. Due to the growing demand for blue calico, the popularity of indigo cultivation also promoted the development of the indigo industry.

The local dyeing raw materials and the convenient process of self-spinning and self-weaving have enabled the dyeing and weaving industry in Jianghai area to develop rapidly and gradually become a well-known specialty area in the country. The craftsmanship of blue calico spread from the south of the Yangtze River to the north of the Yangtze River, and from Suzhou and Nantong to all regions of Jiangsu, forming a major production area centered in Jiangsu. In addition to being supplied locally, the products are also sold well all over the country. The printing technique spread and influenced the whole country.