Matted or felted sheet, usually made of cellulose fibres, formed on a wire screen from water suspension. Source materials include wood pulp, rags, and recycled paper. The fibres are separated (by processes that may be mechanical, chemical, or both) and wetted to produce paper pulp, or stock. The pulp is filtered on a woven screen to form a sheet of fibre, which is pressed and compacted to squeeze out most of the water. The remaining water is removed by evaporation, and the dry sheet is further compressed and often (depending on the intended use) coated or infused with other substances. Types of paper in common use include bond paper, book paper, bristol (or bristol board), groundwood and newsprint, kraft paper, paperboard, and sanitary paper (for towels, napkins, etc.). See alsocalendering; Fourdrinier machine; kraft process.