In fine art, it is a ground or support for drawing, watercolor and pastel painting and for various graphic techniques. Paper is made by interweaving plant or cellulose fibers in sheet form and, depending upon quality, is composed of pulped linen, cotton rags, wood chips or recycled paper. Wood pulp is the basis of lesser quality paper. The paper making process involves beating the fibers to a pulp and drying across a fine, wire-mesh screen. The best watercolor paper is handmade. (See Hand-made Paper). Paper making is thought to have originated in China about 100 A.D., allegedly by Ts'ai Lun, and was introduced in Europe in the 13th Century. Papyrus of ancient Egypt and parchment from Roman times through the Middle Ages were forerunners of modern-day paper. In the 15th century, when books and engravings were first being produced in Europe, paper mills came into being. Today some artists make their own paper, but commercial paper is more prevalent among artists. However different techniques require different selections for texture and quality. Pastel works best with rough paper, and pen and ink is best suited to a smooth surface. Sources: Ralph Mayer, "A Dictionary of Art Terms and Techniques"; Kimberley Reynolds & Richard Seddon, "Illustrated Dictionary of Art Terms"