Silk screening, or seriography, is basically a printing method that uses fabric as a screen to separate a stencil from the surface. Although a patent for the use of silk in particular was awarded to Englishman Samuel Simon in 1907, there has been a long history of printing with other fabrics. A process for applying more than one pigment was subsequently developed in San Francisco by John Pilsworth. Silk has since been replaced by modern polyesters, though the process retains the original name.
Obviously, some frame is required to hold the target surface in place. Paint or ink is applied with a brush, roller or squeegee. Applied pressure pushes the pigment through the fabric mesh in areas exposed through the stencil. Stencils are developed by a variety of methods. For example, a photographic technique involves exposure of the image onto a light-sensitive emulsion. Stencils can also be cut from special films by computer.
Silk screening was a common technique in pop art for transferring mass-produced images to canvas (e.g. Andy Warhol). It remains a major process in the printing industry.
Web sources: inventors.about.com, www.howstuffworks.com, www.albury.net.au