Discharge ink is a type of ink used primarily on dark colored organic fabrics. The ink contains a chemical called a discharge agent that, when heated, removes the dye in the fabric and creates a bleached surface. The ink also contains pigments/dyes that are printed into the fabric as well, and revealed by the discharge agent. The result is similar to water based ink on a white tee, resulting in a vibrant, opaque print but on a dark colored fabric. Discharge ink is often used to achieve a soft, vibrant look on t-shirts. However it only works on organic materials with certain dyes (does not work on cotton pigment dyed items). When used on tri-blends (partially organic, partially synthetic materials), it can result in a more vintage look.