Paper used in furniture design. Watercolor paper has a long history of production and use. The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in micrometers (µm) in the rest of the world. Paper may be between thick. Paper is often characterized by weight. In the United States, the weight assigned to a paper is the weight of a ream, 500 sheets, of varying "basic sizes", before the paper is cut into the size it is sold to end customers. For example, a ream of 20 lb,
Ruled paper lighter lines 2 mm (appx. 5/64 in) apart between each pair of heavy lines. Heavy vertical lines are spaced 8 mm (appx. 5/16 in) apart, beginning 16 mm (appx. 5/8 in) from the left-hand edge of the page. These sheets of paper are generally known as "grands carreaux" (large tiles) as opposed to the "petits carreaux" (small tiles) which are 5x5mm. Seyès ruled paper is available in single sheets ("copies simples") or joined double sheets ("copies doubles") which are sometimes preferred for exams, being easier to handle. DIN 16552:1977-04 (“Lines for handwriting”) specifies the types of ruled paper to be