Metric typographic units
Encyclopedia
Metric typographic units have been devised and proposed several times to overcome the various traditional point systems
. After the French revolution
of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement few decades earlier. The conversion did not happen, though. The Didot point was metrically redefined as m in 1879 by Berthold.
With the introduction of phototypesetting
in the 1970s metric units were increasingly used in typography. The Didot point was redefined once again to 375 μm exactly ( mm). Furthermore a new unit, the quart (quarter millimetre, abbreviated ‘q’) of 250 μm ( mm) was devised.
Otl Aicher vividly encouraged the use of the quart, also providing a suggested list of common sizes.
Note that Aicher’s font sizes are based on the DIN standard then in development, which uses the H-height, whereas in lead typesetting the larger cap height was used. Some typographers have proposed using the x-height
instead, because the psychological size depends more on the size of default, lowercase letters.
The advent and success of desktop publishing
(DTP) software and word processor
s for office use, coming mostly from the non-metric United States
, basically revoked this metrication process in typography. DTP commonly uses the PostScript
point, which is defined as of an inch (352.(7) μm).
To convert dpi resolution to μm resolution, the formula to be used is , where R is the resolution in dpi. So for example 96 dpi translates to a resolution of 265 μm.
The CSS3 media queries draft introduces a unit dpcm
(dots per centimetre) for resolution.
Point (typography)
In typography, a point is the smallest unit of measure, being a subdivision of the larger pica. It is commonly abbreviated as pt. The point has long been the usual unit for measuring font size and leading and other minute items on a printed page....
. After the French revolution
French Revolution
The French Revolution , sometimes distinguished as the 'Great French Revolution' , was a period of radical social and political upheaval in France and Europe. The absolute monarchy that had ruled France for centuries collapsed in three years...
of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement few decades earlier. The conversion did not happen, though. The Didot point was metrically redefined as m in 1879 by Berthold.
With the introduction of phototypesetting
Phototypesetting
Phototypesetting was a method of setting type, rendered obsolete with the popularity of the personal computer and desktop publishing software, that uses a photographic process to generate columns of type on a scroll of photographic paper...
in the 1970s metric units were increasingly used in typography. The Didot point was redefined once again to 375 μm exactly ( mm). Furthermore a new unit, the quart (quarter millimetre, abbreviated ‘q’) of 250 μm ( mm) was devised.
Otl Aicher vividly encouraged the use of the quart, also providing a suggested list of common sizes.
| Use case (name) | q | mm | μm | dd | pt | pp |
|---|---|---|---|---|---|---|
| (Pearl) | 7 | 1750 | 5.0 | 5.0 | ||
| Footnote (Nonpareille) | 9 | 2250 | 6 | 6.4 | 6.4 | |
| Table | 10 | 2500 | 7.1 | 7.1 | ||
| Legend | 11 | 2750 | 7.8 | 7.8 | ||
| Newspaper (Petite) | 12 | 3 | 3000 | 8 | 8.5 | 8.5 |
| Book small | 13 | 3250 | 9.2 | 9.2 | ||
| Book large | 14 | 3500 | 9.9 | 10.0 | ||
| Foliant (Corpus) | 15 | 3750 | 10 | 10.6 | 10.7 | |
| Title (Cicero) | 18 | 4500 | 12 | 12.8 | 12.8 |
Note that Aicher’s font sizes are based on the DIN standard then in development, which uses the H-height, whereas in lead typesetting the larger cap height was used. Some typographers have proposed using the x-height
X-height
In typography, the x-height or corpus size refers to the distance between the baseline and the mean line in a typeface. Typically, this is the height of the letter x in the font , as well as the u, v, w, and z...
instead, because the psychological size depends more on the size of default, lowercase letters.
The advent and success of desktop publishing
Desktop publishing
Desktop publishing is the creation of documents using page layout software on a personal computer.The term has been used for publishing at all levels, from small-circulation documents such as local newsletters to books, magazines and newspapers...
(DTP) software and word processor
Word processor
A word processor is a computer application used for the production of any sort of printable material....
s for office use, coming mostly from the non-metric United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, basically revoked this metrication process in typography. DTP commonly uses the PostScript
PostScript
PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. It is best known for its use as a page description language in the electronic and desktop publishing areas. Adobe PostScript 3 is also the worldwide printing and imaging...
point, which is defined as of an inch (352.(7) μm).
Device resolutions
The resolution of computer screens is often denoted in millimetres pitch, whereas office printers are usually denoted reciprocally in dots per inch (‘dpi’, ‘d/in’). Phototypesetters have long used micrometres.To convert dpi resolution to μm resolution, the formula to be used is , where R is the resolution in dpi. So for example 96 dpi translates to a resolution of 265 μm.
The CSS3 media queries draft introduces a unit dpcm
Dpcm
Dots per centimetre or dpcm is a unit of resolution, used as a metric alternative to dots per inch/dpi.It is used in CSS3 media queries, among other standards....
(dots per centimetre) for resolution.