Typographic unit

A ruler showing 4 scales (from the top down): Inches, Points, Picas, and Agates
Diagram of font metrics showing where letters and symbols would be placed relative to each other. The letters would change size according to the font type, typographic unit and dimension used.

Typographic units are the units of measurement used in typography or typesetting. Traditional typometry units are different from familiar metric units because they were established in the early days of printing. Though most printing is digital now, the old terms and units have persisted.

Even though these units are all very small, across a line of print they add up quickly. Confusions such as resetting text originally in type of one unit in type of another will result in words moving from one line to the next, resulting in all sorts of typesetting errors (viz. rivers, widows and orphans, disrupted tables, and misplaced captions). Before the popularization of desktop publishing, type measurements were done with a tool called a typometer.[1]

  1. ^ Radics, Vilmos; Ritter, Aladár (1984). Make-up and typography. International Organization of Journalists. p. 13. ISBN 9789630231367. Retrieved 25 November 2016. The typometer is an instrument for measuring typographical denominations: type sizes, column width and depth, slugs, type area, etc.