Screen printing originated in China during the Song Dynasty and later spread to other Asian countries and Europe. It was first patented in England in 1907 and used mainly for wallpaper printing. In the 1960s, Andy Warhol popularized screen printing in the US with depictions of Marilyn Monroe. Screen printing involves forcing ink through a porous fabric with a stencil design to produce an image. It can print on many substrates and is used commercially and in fine arts. The key tools and processes include frames, screens, stencils, inks, and squeegees.