Watermark

Watermark is an image or mark on a sheet of paper, visible when the sheet is viewed against the light. The mark is produced by variation in the thickness of the paper within a single sheet: during handmade papermaking, a thin wire design is attached to the wire mesh mould, and in those places less fibre settles, so the paper becomes slightly thinner and lets through more light. Watermarks appeared in Italian papermaking at the end of the thirteenth century and initially served as the marks of workshops or paper mills. Over time they became important for establishing the origin and dating of paper. For art historians, watermarks are a valuable tool for studying old drawings, prints, and manuscripts: analysis of the mark helps to determine when and where a sheet was made, and thus to refine the attribution and dating of a work. Watermarks are also used as a means of protection against forgery — on banknotes, documents, and postage stamps. In the artistic context, the study of watermarks is part of the technical examination of works on paper.