Blue calico from Wuzhen, Tongxiang.

Blue calico is a type of Chinese handicraft, a traditional hollowed-out white paste anti-dyeing print, also known as indigo blue cloth, commonly known as medicine spot cloth, pouring flower cloth, etc. It is a traditional Chinese handicraft printing and dyeing product, hollowed-out white paste anti-dyeing printing, which has a history of 1,300 years. The main producing areas include Nantong City, Jiangsu Province, Tongxiang City, Zhejiang Province, Shaoyang City, Hunan Province, Lanling County, Shandong Province, etc. Originally dyed with blue grass. Blue calico uses lime and soybean powder to synthesize gray paste and roast blue. It is made by all-cotton, all-hand spinning, plate engraving, scraping paste and other printing and dyeing processes. Blue calico in a broad sense: including tie-dyeing, batik, clamp dyeing and gray dyeing. Traditional tie-dyeing, batik, clamp dyeing and gray dyeing are mostly dyed with indigo blue. Although the anti-dyeing methods are different, the finished products are all blue and white flower cloths, so they can be collectively referred to as blue calico. The common point is that the material is cloth (or hand-woven cloth), the dye is plant indigo blue, and the production process is manual operation. Blue calico in a narrow sense: People have long been accustomed to calling the gray-dyed blue and white flower cloth dyed with plant blue grass, dyed with soybean powder and lime powder, and paper-cut as a version, and filtered paste as blue calico.