Blue printed fabric is an ancient handicraft in China, also known as indigo patterned fabric or medicine patterned fabric. It is a textile made from cotton or hemp as raw materials, using lime and soybean powder to synthesize a mortar for baking blue, and then using hollowed out white paste anti dyeing printing. The production process of blue printed fabric is complex and delicate, including the following steps: designing patterns, making hollow plates, brushing, dyeing, drying, scraping, and so on. Among them, the hollow out plate is a key tool for making blue printed fabric, and carving requires exquisite craftsmanship and care. During the dyeing process, dyes made from blue grass can give the fabric a vibrant color.