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Typographic unit

Typographic units are different from common metric units, as they were established earlier. In Europe, the Didot point system was created by François-Ambroise Didot (1730–1804) in c. 1783. Didot’s system was based on Pierre Simon Fournier’s (1712–1768), but Didot modified Fournier’s by adjusting the base unit precisely to a French Royal inch (pouce), as Fournier’s unit had not conformed precisely to any standard unit.

(Fournier’s printed scale of his point system, from Manuel Typographique, Barbou, Paris 1764, enlarged)

However, the basic idea of the point system – to generate different type sizes by multiplying a single minimum unit calculated by dividing a base measurement unit such as one French Royal inch – was not Didot’s invention, but Fournier’s.¹ In Fournier’s system, an approximate French Royal inch (pouce) is divided by 12 to calculate 1 ligne, which is then divided by 6 to get 1 point. Didot just made the base unit (one French Royal inch) identical to the standard value defined by the then government.

In Didot’s point system:

  • 1 point = 1/6 ligne = 1/72 French Royal inch = 1082797949/2880000000 mm = approx. 0.3759 mm

Both in Didot’s and Fournier’s systems, some point sizes have traditional names such as Cicero (before introduction of point systems, type sizes were called by names such as Cicero, Pica, Ruby, Long Primer, etc).

  • 1 cicero = 12 Didot points = 1/6 French Royal inch = 1082797949/240000000 mm = approx. 4.5117 mm

The Didot point system has been widely used in European countries.

In Great Britain and the U. S. A., many proposals for type size standardization had been made by the end of 19th century (such as Bruce Typefoundry’s mathematical system that was based on a precise geometric progression). However, no nation-wide standard was created until the American Point System was decided in 1886.

The American Point System was proposed by Nelson C. Hawks of Marder Luse & Company in Chicago in the 1870s, and his point system used the same method of size division as Fournier’s; viz. dividing 1 inch by 6 to get 1 pica, and dividing it again by 12 to get 1 point. However, the American Point System standardized finally in 1886 is different from Hawks’ original idea in that 1 pica is not precisely equal to 1/6 inch (Imperial or American/British inch), as the United States Type Founders’ Association defined the standard pica to be the Johnson Pica which had been adopted and used by Mackellar, Smiths and Jordan type foundry (MS&J), Philadelphia. As MS&J was very influential in those days, many other type foundries were using the Johnson Pica.² Also, MS&J defined that 83 Picas are equal to 35 centimeters.

The Johnson Pica was named after Lawrence Johnson who had succeeded Binny & Ronaldson in 1833. Binny & Ronaldson was one of the oldest type foundries in the United States, established in Philadelphia in 1796. Binny & Ronaldson had bought the type founding equipment of Benjamin Franklin’s (1706–1790) type foundry established in 1786 and run by his grandson Benjamin Franklin Bache (1769–1798). The equipment is thought to be that which Benjamin Franklin purchased from Pierre Simon Fournier when he visited France for diplomatic purposes (1776–1785).

In the American Point System:

  • 1 pica = 35/83 centimeters = approx. 0.1660 inch
  • 1 point = 1/12 pica = 175/498 mm = approx. 0.3514 mm

The American Point System has been used in the U.S.A., Great Britain and many other countries including Japan.

Today, digital printing and display devices and page layout softwares are using a unit that is different from these traditional typographic units. On many digital printing systems (desk-top publishing systems in particular), the following equations are applicable (with exceptions).

  • 1 pica = 1/6 inch (British/American inch of today)
  • 1 point = 1/12 pica = 1/72 inch = 127/360 mm = approx. 0.3528 mm

You can see that Fournier’s original method of division is restored in today’s digital typography. This seems to prove the timeless value of Fournier’s invention.

Table of contents


¹ Actually, Sebastien Truchet (1657–1729) had invented a similar type sizing system before Fournier implemented his point system. Truchet’s system was applied to the types of the Imperiemerie Royal, the romains du roi. It is thought that Fournier knew about Truchet’s scheme that was based on the standard French Royal inch and a very fine unit of 1/204 ligne. For further information on Truchet’s sytem, refer to James Mosley’s “The New Type Bodies of the Imprimerie Royale”, pp. 400–408, Vol. 3, The Manuel Typographique of Pierre-Simon Fournier le jeune, Darmstadt 1995. and Jacques André's “Truchet & Types” (http://www.irisa.fr/faqtypo/truchet/truchet1E).

² Regarding the background of the adoption of the Johnson Pica, Mr. Richard L. Hopkins, author of Origin of The American Point System says: “The major issue then was the expense involved in re-tooling literally hundreds of molds in each foundry to make them all conform to the new system. If they could avoid just a few sizes being altered, it would save hundreds of thousands of dollars. That is why the MS&J (Johnson) pica was adopted.”

Metric Units

The traditional typographic units are based either on non-metric units, or on odd multiples (such as 35/83) of a metric unit. There are no specifically metric units for this particular purpose, although there is a DIN standard sometimes used in German publishing, which measures type sizes in multiples of 0.25 mm, and proponents of the metrication of typography generally recommend the use of the milimetre for typographical measurements, rather than the development of new specifically typographical metric units.

Select Bibliography

  • Boag, Andrew. “Typographic measurement: a chronology”, Typography papers, no. 1, 1996, The Department of Typography and Graphic Communication, The University of Reading, Reading 1996.
  • Bruce’s Son & Company, Specimen of Printing Types, incl. Theo. L. DeVinne’s “The Invention of Printing”, New York 1878.
  • Carter, Harry. Fournier on Typefounding, The Soncino Press, London 1930.
  • Fournier, Pierre Simon, The Manuel Typographique of Pierre-Simon Fournier le jeune, Vols. I–III, Ed. by James Mosley, Darmstadt 1995.
  • Fournier, Pierre Simon. Modèles des Caractères de l’Imprimerie, including James Mosley’s introduction, Eugrammia Press, London 1965.
  • Fournier, Pierre Simon. Manuel Typographique, Vols. I & II, Fournier & Barbou, Paris 1764–1766.
  • Hansard, T. C. Typographia,, Baldwin, Cradock, and Joy, London 1825.
  • Hopkins, Richard L. Origin of The American Point System, Hill & Dale Private Press, Terra Alta 1976.
  • Hutt, Allen. Fournier, the compleat typographer, Rowman and Littlefield, Totowa, NJ 1972.
  • Johnson, John. Typographia, Longman, Hurst, Rees, Orme, Brown & Green, London 1824.
  • Jones, Thomas Roy, Printing in America, The Newcomen Society of England, American Branch, New York 1948,
  • MacKellar Smiths & Jordan. One Hundred Years, Philadelphia 1896.
  • Mosley, James. “French Academicians and Modern Typography: Designing New Types in the 1690s”, Typography papers, no. 2, 1997, The Department of Typography and Graphic Communication, The University of Reading, Reading 1997.
  • Moxon, Joseph. Mechanick Exercises On The Whole Art Of Printing, Oxford University Press, London 1958.
  • Ovink, G. Willem. “From Fournier to metric, and from lead to film”, Quaerendo, Volume IX 2 & 4, Theatrum Orbis Terrarum Ltd., Amsterdam 1979.
  • Smith, John. The Printer’s Grammar, L. Wayland, London 1787.
  • Yamamoto, Taro. pt – Type Sizing Units Converter, http://www.kt.rim.or.jp/~tyamamot/pt.htm Tokyo 2001.

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