Totally Spaced

In the days of handset type, there were only fixed-size spaces, carefully proportioned from the type body. Every line of composed type was set by careful professionals, guided by rules but relying on their sensitivity and expertise.

Units of space were developed as specific fractional segments based on the em, a linear measurement equal to the point size of the typeface. In 10 point type, the em is 10 points wide; in 12 point type, 12 points wide; and so forth. Classically, an em was defined as the width of the “M” in the given point size. This became less appropriate with the development of modern typefaces in which the M’s were designed narrower than an em, and completely irrelevant as people began to set type for languages in which M does not exist.

There were four ubiquitous spaces – thick, middle, thin, and hair – the thickest of which was less than an en (an en being half of an em). When more horizontal space was needed, typesetters turned to the quadrat (from the Latin, quadratus, squared).1 These precisely sized typographic blanks were used for indents, larger spacing, the creation of white lines, and the filling up of short lines. They were sized as follows: en, em, two-, three-, and four-em.2 When setting poetry, special quadrats were sometimes cast to insure the proper alignment of uniquely set lines.3 Over time, “quadrat” was conversationally abbreviated to “quad”, and with the introduction of machine-set and digital type, the term was generally supplanted by references to en-, em-, and multiple-em spaces.

Space dimensions can be expressed and specified as ratios or fractions. A thin space would be 5 to em (i.e. five spaces per em), or 5:M. Bringhurst prefers the fractional form: M/5 (i.e. an em divided by five, or one-fifth of an em).

The traditional spaces and quads are illustrated as follows:

hair space



thin space



middle space



thick space



patent space




en quad


em quad


2 em quad


3 em quad


4 em quad



The hair space was used to assist in the justification of flush lines, and to gently nudge certain character pairs. In classic typography, there was no strict definition for the width of a hair space. As a general rule, anything thinner than M/5 was considered a hair space, but more typically, they leaned to the fatter end of M/7–M/10. There is no agreement amongst modern digital typesetting authorities as to its size. In their character design standards (which basically echo the Unicode specification), the Microsoft Typography group recommends the hair space be set to M/10–M/16, while Adobe InDesign defines it as M/24. It would be mechanically impossible to create anything approaching these modern designations in the age of metallic type.

The middle space was also referred to as the “middling” space, and the decades following World War II saw its name truncated to simply “mid” space.6

British authors Southward and Powell lament the lack in their own country of the American “patent space”, which they describe as being midway between the thick space and an en quad (so presumably M/2.5).7 The purpose or application that gave its name to this space is unclear; whatever its function, it was specialized enough that it did not see widespread use. It’s included here as a curiosity; although rendered obscure by the passage of time, it was notable enough in its day to be mentioned by prominent authorities.

Bridging the eras of hand- and machine-set type, the fourth edition of the University of Chicago Press Manual of Style has its own interesting way of describing available spaces and their dimensions:8


260. On the linotype machine the pica system of measurement is used. There are three “fixed” spaces (see 261): the em quad, the en quad, and the thin space, which is equal to a 4-em space. To spread the spaces, a space band is used; this band can spread a space to any size between a 3-em space and a space a trifle larger than an en quad. If a space smaller than a thin space is required, it must be put in by hand.



261. An em, em quad, or simply quad (=quadrat) is a block of type the top of which forms a perfect square. A 12-pt. quad is thus a piece of metal one-sixth of an inch square at the ends. The term em is also used of the size of such a square in any given size of type as a unit of measurement. “Indent 8-pt. 2 ems” thus means that the line should be indented 16 points. An em dash is a dash the width of an em.

Two- and three-em quads are multiples of the above, cast in one block of type-metal. Two- and three-em dashes are dashes the width of 2- and 3-em quads respectively.

An en quad is half the size of an em quad in width. Thus an 8-pt. en quad is 4 points wide (thick) and 8 points long (deep). An en dash is a dash the width of an en quad.

A three-em space is one-third of an em in thickness. This is also called a thick space, and is the standard space used to separate words.

A four-em space is one-fourth of an em; a five-em space is one-fifth of an em. Four- and 5-em spaces are also called middle and thin spaces.

A hair space is any space thinner than a 5-em.

While the aforementioned list sums up the arsenal of spaces at the disposal of traditional typesetters, it is not uncommon to encounter several other named spaces:

figure space

Introduced by the Mergenthaler Linotype Company (founded 1886) for use in their typesetting machines, this is a specially sized space the same width as a numeral. This was to insure that tables of figures would stay aligned (0–9 being designed to be of roughly equal width), and was used only in that context. In body text, normal word spacing would be used to set figures. The eleventh edition of the Manual of Style makes reference to linotype matrices (molds) for “en quad (or figure space)”, implying that they are interchangeable.10

This bit of humor appeared in The Typographic Journal: “Let’s ‘shoot the chutes,’ ” said the quad to the figure space. And then both dropped on to the assembler belt.11

hard space

Like the word space, this has no specifically defined size, but rather a special characteristic that prevent it from breaking at line endings. Also refered to as a no-break space.

punctuation space

Akin to the figure space, the punctuation space is variously defined as being the width of a period or comma, and is used to align numbers in tables. This space seems only to exist in modern contexts. I could find no references to its existence before the advent of desktop publishing software in the 1980’s.

word space

This is not an actual sized space, as such, but rather a way to refer to the space between words. Typically, M/3–M/5.

Because a room full of people setting metallic type is anything but quiet, phonetic alphabet terms were employed to lessen the chances of verbal instructions being rendered unintelligible by the din. An em was referred to as a “mutton”, while an en was dubbed a “nut”.


1 Savage, William. A Dictionary of the Art of Printing. (London: Longman, Brown, Green, and Longmans, 1841), 670.

2 Southward, John and Arthur Powell. Practical Printing. 2nd ed. (London: J.M. Powell & Son, 1884), 8.

3 Adams, Thomas F. Typographia. (Philadelphia: Thomas F. Adams, 1837), 83–4.

4 Unicode Consortium, The. The Unicode Character Code Charts, v.5.1. (Mountain View, CA), 183.

5 Allen, Julie D. ... [et al.], eds. The Unicode Standard 5.0 (Upper Saddle River, NJ: Addison-Wesley, 2006), 205.

6 Jacobi, Charles Thomas. Printing : A Practical Treatise on the Art of Typography. 4th ed., Revised. (London: George Bell and Sons, 1908), 28.

7 Southward and Powell, 89–90.

8 Miller, Newman, dir. Manual of Style. (Chicago: University of Chicago Press, 4th ed., 1914), 99–101, 109.

9 Mergenthaler Linotype Company. Linotype Specimen Faces. (New York: Mergenthaler Linotype Company, January 1907), 8.

10 University of Chicago Press. A Manual of Style. (Chicago: University of Chicago Press, 11th ed., 1949), 267.

11 Bramwood, J.W., ed. The Typographical Journal v.26. (Indianapolis: International Typographical Union, January 1905), 454.


Bringhurst, Robert. The Elements of Typographic Style. 2nd ed. Vancouver: Hartley & Marks, Publishers, 2002.

Reed, Talbot Baines. A History of the Old English Letter Foundries. London: Elliot Stock, 1887.

Ringwalt, J. Luther, ed. American Encyclopedia of Printing. Philadelphia: Menamin & Ringwalt, 1871.

Tschichold, Jan. Composition Rules. Private: Penguin Books Internal Staff Memo, 1947.


1 Word- and letter-spacing illustrated. [Manual of Style, 4th ed., 1914. pg 101.]