Typometer

A typometer is a ruler which is usually divided in typographic points or ciceros on one of its sides and in centimeters or millimeters on the other, which was traditionally used in the graphic arts to inspect the measures of typographic materials. The most developed typometers could also measure the type size of a particular typeface, the leading of a text, the width of paragraph rules and other features of a printed text. This way, designers could study and reproduce the layout of a document.

One of the domains where the typometer was most widely used was the editorial offices of newspapers and magazines, where it was used along with other tools such as tracing paper and linen testers to define the layout of the pages of the publications, until the 1980s.

Typometers were initially made of wood or metal (in later times, of transparent plastic or acetate), and were produced in diverse shapes and sizes. Some of them presented several scales that were used to measure the properties of the text. Each scale corresponded with a type size or with a leading unit, if line blocks were divided by blank spaces. However, typometers could not be used to measure certain computer-generated type sizes, that could be set in fractions of points.

Due to the technological advancements in desktop publishing, that allow for a greater precision when setting the type size of texts, typometers have disappeared from most graphic design related professions. It keeps being used, even today, by traditional printers who still employ type metal.

The idea of organising type sizes according to a particular point system first appeared during the 18th century, in the 1723 book La Science pratique de l'imprimerie, written by French printer and bookseller Martin-Dominique Fertel. In 1737, French engraver and typecaster Pierre-Simon Fournier (called Fournier the young) invented a tool in the shape of a square that he called prototype, which allowed him to accurately measure type sizes. He also stablished the Fournier point, that could be used for the first time to set a correlation between a type size and a constant number of points. According to his own words,

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