Foil Block Print
From The Giant: The Definitive Obey Giant Site
From Technologystudent.com: In its simplest form, Foil Block Printing (sometimes called Hot Foil Stamping) is where a pre-glued metallic foil, is pressed by a heated die, into the surface of a material. This is a permanent way of applying a quality finish to materials, such as card, for packaging. This process can also be used to apply a finish to other materials including leather.
The foil is metallic, but comes in a range of colours including gold, copper, red and purple. It is even possible to block print holographic foils, creating 3D effects. Foils are also available as satin, gloss and matt.