Hot stamping is a dry printing method of lithography in which predried ink or foils are transferred to a surface at high temperatures. The non-polluting method has diversified since its rise to prominence in the 19th century to include a variety of colors and processes. Widely used on plastic and paper (where it is a common technique in security printing, it is applicable to other sources as well.
In a hot stamping machine, a die is mounted and heated, with the product to be stamped placed beneath it. A metallized or painted roll-leaf carrier is inserted between the two, and the die presses down through it. The dry paint or foil used is impressed into the surface of the product. The dye-stamping process itself is non-polluting because the materials involved are dry.