Silkscreening is thought to have originated in ancient China. It gained popularity in the 1960s due to the work of artists like Warhol and Lichtenstein - in the art world it is called serigraphy.
The process involves burning an image onto a screen (one for each color) then using a squeegee to push ink or dye through the screen and onto the substrate. Ink can be printed on to virtually any substrate. Acid based dyes are silkscreened onto nylon. Screen printing with acid dye creates the best penetration of fabric, with bold colors on each side that resist fading due to ultraviolet exposure.