ennage

Ennage is the total count of ens used in a typesetting job, where one en equals half the width of an em, the basic unit of horizontal measurement in metal type. In a font of 12 point type, an em is 12 points wide, so an en is 6 points. The ennage therefore measures the aggregate horizontal space consumed by all the characters, spacing, and leads in a composed page or job.

This measurement mattered most in jobbing shops and newspaper compositoriums where type was rented from foundries or used from standing stock. Since metal type was expensive and space in cases limited, printers needed to know exactly how much type a job would consume before committing materials. A compositor could estimate ennage from copy by counting characters and applying average widths for the typeface in question, or could measure it directly from the composed form using a line gauge.

Variants and calculation

The term itself derives from the letter N, which was historically taken as a standard average character width in many typefaces, hence the name of the unit. Some shops calculated ennage per line and summed across all lines; others estimated bulk ennage from word count and average character width. The precision varied: a rough estimate might suffice for internal scheduling, while a precise ennage was needed for billing when type rental was charged by the unit consumed.

Ennage became less critical with the rise of photocomposition and later digital typesetting, since these technologies did not consume physical stock in the same way. However, the underlying measurement system persisted in point-based design software, where an en space remains half the em width by definition. The term itself has largely passed from active use in modern printing, preserved mainly in historical texts and in specialized work involving metal type composition or in the design vocabularies built on typographic measurement.