Silverpoint (from Wikipedia)
A silverpoint drawing is made by dragging a silver rod or wire across a surface, often prepared with gesso or primer. Silverpoint is one of several types of metalpoint used by scribes, craftsmen and artists since ancient times. Metalpoint styli were used for writing on soft surfaces (wax or bark), ruling and underdrawing on parchment, and drawing on prepared paper and panel supports. For drawing purposes, the essential metals used were lead, tin and silver. The softness of these metals made them effective drawing instruments. (Watrous, 1957) Goldsmiths also used metalpoint drawings to prepare their detailed, meticulous designs.
In the late Gothic/early Renaissance era, silverpoint emerged as a fine line drawing technique. Not blunting as easily as lead or tin, and rendering precise detail, silverpoint was especially favored in Florentine and Flemish workshops. Silverpoint drawings of this era include model books and preparatory sheets for paintings. Artists who worked in silverpoint include Jan van Eyck, Leonardo da Vinci, Albrecht Dürer and Raphael. Cennino Cennini’s “Il Libro dell’Arte” provides a window on the practice of silver and leadpoint drawing, as well as preparing metalpoint grounds, in the late 14th century.