The border or edge space separating or surrounding printed matter on a page. Standard proportion stipulates that the bottom margin is larger than the top, and the top margin is larger than the sides. Progressive proportion stipulates that the inside margin is the smallest, the top next larger, the outside is next larger, and the bottom margin is largest; such that the progression runs clockwise on recto pages, and counter-clockwise on verso pages. The white space between columns is also a margin, sometimes called an "internal margin" (as distinguished from "external margins" at the edges), with or without a column rule. See valley, gutter, apron, white space, air, river, attic; compare sinkage.