Bristol board

A stiff cardboard that has smooth finish and is suitable for drawing and painting with water-based paint. It can be used on both sides and is popular for ink drawing and diagrams because of the sharpness of effect that can be achieved. The U.S. Patent Office specifies that Bristol Board must be used for trademark and patent drawings. Source: Ralph Mayer, "A Dictionary of Art Terms and Techniques"<br><br>A sturdy drawing surface used for many types of two-dimensional artwork, including lettering. It is available in several finishes, including a smooth plate finish and a medium vellum. It can be used on both of its sides.Also see card or cardboard, illustration board, oaktag, and paper.