Scraperboard or scratchboard refers to both a medium, and an illustrative technique using sharp knives and tools for etching into a thin layer of white China clay that is coated with black India ink. Scratchboard can also be made with several layers of multi-colored clay, so the pressure exerted on the instrument used determines the color that is revealed. There is also foil paper covered with black ink that, when scratched, exposes the shiny surface beneath. Scratchboard can be used to yield highly detailed, precise and evenly textured artwork.