Tie-dye is a method of dyeing clothing or fabric originally popularized by members of the hippie subculture. Clothes are tied, either with string or rubber bands into some sort of pattern. Then the clothes are dyed, either by submerging them or by squirting dye solution onto them. Some areas, where the fabric is tied and in inner parts of folds, do not absorb dye as readily, forming a pattern. This is known as a resist technique (the areas that are tied and the inner parts of folds resist dyeing). Patterns are also formed by applying different color dyes to different sections of the fabric.
Although many different kinds of dyes may be used, most tie-dyers now dye with Procion MX fiber reactive dyes. This class of dyes works at warm room temperatures and the molecules bind with cellulose based fibers (cotton, rayon, hemp, linen) permanently when the pH is raised. Soda ash (sodium carbonate) is generally used to raise the pH and is either added directly to the dye, or in a solution of water in which garments are soaked before dyeing. They do not fade with washing, but sunlight will cause the colors to fade over time.
Shibori is a form of tie-dye which originated in Japan, which has been practiced there since at least the eighth century. Shibori includes a number of labor-intensive resist techniques including stitching elaborate patterns and tightly gathering the stitching before dyeing, forming intricate designs for kimonos. Another shibori method is to wrap the fabric around a core of rope, wood or other material, and bind it tightly with string or thread. The areas of the fabric that are against the core or under the binding would remain undyed.
Tie-dye techniques have also been used for centuries in the Hausa region of West Africa, with renowned indigo dye pits located in and around Kano, Nigeria. The tie-dyed clothing is then richly embroidered in traditional patterns. It has been argued that the Hausa techniques were the inspiration for the hippie fashion.
Plangi and tritik are Malay-Indonesian words for methods related to tie-dye, and banda is a term from India. Ikat is a method of tie-dying the warp or weft before the cloth is woven.