The image is scratched into the medium, rather than painted on in the traditional manner. It is a direct process, unlike engravings, etchings or linocuts, which
are printing processes. The medium itself consist of a sheet of board, which is compressed with white chalk and clay. It is then sprayed (overlaid) with a matt black ink.
To create the image, the artist uses a sharp, (usually arrow-shaped) metal instrument, to scratch away the black surface and reveal the white area. The medium allows for intricate detail, sharp contrast, and a wide range of textures. Shadows and highlights are created by "scratching" away at the board.