Point (typography)
Template:Short description Template:About Template:Redirect-distinguish Template:Infobox unit In typography, the point is the smallest unit of measure. It is used for measuring font size, leading, and other items on a printed page. The size of the point has varied throughout printing's history. Since the 18th century, the size of a point has been between 0.18 and 0.4 millimeters. Following the advent of desktop publishing in the 1980s and 1990s, digital printing has largely supplanted the letterpress printing and has established the desktop publishing (DTP) point as the de facto standard. The DTP point is defined as Template:Frac of an inch (or exactly 0.352Template:Overline mm) and, as with earlier American point sizes, is considered to be Template:Frac of a pica.
In metal type, the point size of a font describes the height of the metal body on which that font's characters were cast. In digital type, letters of a computer font are designed around an imaginary space called an em square. When a point size of a font is specified, the font is scaled so that its em square has a side length of that particular length in points. Although the letters of a font usually fit within the font's em square, there is not necessarily any size relationship between the two, so the point size does not necessarily correspond to any measurement of the size of the letters on the printed page.<ref name=Phinney>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Citation</ref>
HistoryEdit
The point was first established by the Milanese typographer, Francesco Torniella da Novara (Template:Circa – 1589) in his 1517 alphabet, L'Alfabeto. The construction of the alphabet is the first based on logical measurement called "Punto," which corresponds to the ninth part of the height of the letters or the thickness of the principal stroke.<ref name="alp">Template:Cite book</ref><ref>Template:Cite book</ref>
NotationsEdit
A measurement in points can be represented in three different ways. For example, 14 points (1 pica plus 2 points) can be written:
- Template:Frac (12 points would be just "Template:Frac")—traditional style
- 1p2 (12 points would be just "1p")—format for desktop
- 14pt (12 points would be "12pt" or "1pc" since it is the same as 1 pica)—format used by Cascading Style Sheets defined by the World Wide Web Consortium.<ref>Template:Citation</ref>
Varying standardsEdit
| Name | Year | mm | inch | |
|---|---|---|---|---|
| ≈ Template:Val | ||||
| Fournier<ref>Various sources give different sizes, namely: ≈ Template:Val, ≈ Template:Val, ≈ Template:Val, (exactly) Template:Val, ≈ Template:Val, ≈ Template:Val.</ref> | 1737 | ≈ 0.345 | Template:Val | |
| American | 1886 | ≈ Template:Val | = Template:Val | |
| Japanese<ref name="JIS Z 8305">JIS Z 8305. 活字の基準寸法. Dimensions of Printing Types.</ref> | 1962 | = Template:Val | ≈ Template:Val | |
| TeX <syntaxhighlight lang="text" class="" style="" inline="1">pt</syntaxhighlight> | 1982 | = 0.Template:Overline | ≈ Template:Val | = Template:Frac |
| PostScript, CSS <syntaxhighlight lang="text" class="" style="" inline="1">pt</syntaxhighlight>, TeX <syntaxhighlight lang="text" class="" style="" inline="1">bp</syntaxhighlight> | 1984 | = 0.352Template:Overline | = 0.013Template:Overline | = Template:Frac |
| ≈ Template:Val | ||||
| Didot | 1783 | ≈ Template:Val | ≈ Template:Val | |
| Berthold | 1878 | ≈ 0.376 | ≈ Template:Val | |
| DIN actual,<ref name="DIN 16507-1">DIN 16507-1:1998 and its predecessors, at least since 1964, for lead typecasting defined 2660 points to measure 1000.333 mm at 20 °C, but for public communication it later introduced a rounder value.</ref> TeX <syntaxhighlight lang="text" class="" style="" inline="1">dd</syntaxhighlight> | 1964 | = Template:Val | ≈ Template:Val | |
| DIN nominal,<ref name="DIN 16507-1"/> TeX <syntaxhighlight lang="text" class="" style="" inline="1">nd</syntaxhighlight> | 1984 | = Template:Val | ≈ Template:Val | |
| Other | ||||
| Truchet | 1694 | ≈ 0.188 | ≈ Template:Val | |
| L'Imprimerie Nationale nominal | 1810 | = 0.400 | ≈ Template:Val | |
| L'Imprimerie Nationale actual | 1810 | = 0.398 77 mm | ≈ Template:Val | |
| DIN,<ref name="DIN 16507-2">DIN 16507-2 (1984, 1999) does not specify a custom unit for electronic typography, but measures using a module.</ref> Japanese, CSS <syntaxhighlight lang="text" class="" style="" inline="1">q</syntaxhighlight> | 1999 | = Template:Val | ≈ Template:Val | |
There have been many definitions of a "point" since the advent of typography. Traditional continental European points at about Template:Val are usually a bit larger than English points at around Template:Val.
French pointsEdit
{{#invoke:Hatnote|hatnote}}
Template:Anchor The Truchet point, the first modern typographic point, was Template:Frac of a French inch or Template:Frac of the royal foot. It was invented by the French clergyman Sébastien Truchet. During the metrication of France amid its revolution, a 1799 law declared the meter to be exactly 443.296 French lines long. This established a length to the royal foot of Template:Frac m or about 325 mm. The Truchet point therefore became equal to Template:Frac mm or about Template:Val. It has also been cited as exactly 0.188 mm.
Template:Anchor The Fournier point was established by Pierre Simon Fournier in 1737.<ref name="Fournier1764">Template:Cite book</ref><ref name="De Vinne-French">Template:Cite book</ref><ref name="LegrosGrant1916" />Template:Rp The system of Fournier was based on a different French foot of c. 298 mm. With the usual convention that 1 foot equals 12 inches, 1 inch (pouce) was divided into 12 lines (lignes) and 1 line was further divided into 6 typographic points (points typographiques). One Fournier point is about 0.0135 English inches.
Fournier printed a reference scale of 144 points over two inches; however, it was too rough to accurately measure a single point.<ref name="De Vinne-French" />
The Fournier point did not achieve lasting popularity despite being revived by the Monotype Corporation in 1927.Template:Citation needed It was still a standard in Belgium, in parts of Austria, and in Northern France at the beginning of the 20th century.<ref name="LegrosGrant1916" />Template:Rp In Belgium, the Fournier system was used until the 1970s and later. It was called the "mediaan"-system.
Template:Anchor The Didot point, established by François-Ambroise Didot in 1783,<ref name="BainesHaslam2005">Template:Cite book</ref> was an attempt to improve the Fournier system. He did not change the subdivisions (1 inch = 12 subdivisions = 72 points), but defined it strictly in terms of the royal foot, a legal length measure in France: the Didot point is exactly Template:Frac of a French foot or Template:Frac of a French inch, that is (by 1799) Template:Frac mm or about Template:Val. Accordingly, one Didot point is exactly two Truchet points.
However, 12 Fournier points turned out to be 11 Didot points,<ref name="De Vinne-French" />Template:Rp giving a Fournier point of about Template:Val; later sources<ref name="LegrosGrant1916" />Template:Rp state it as being Template:Val. To avoid confusion between the new and the old sizes, Didot also rejected the traditional names, thus parisienne became corps 5, nonpareille became corps 6, and so on.<ref name="De Vinne-French" />Template:Rp The Didot system prevailed because the French government demanded printing in Didot measurements.<ref>L. Ronner, Van leerling tot Zetter, 1913, N.V.De nieuwe Tijd, Amsterdam, pag 30.</ref>Template:Better source needed
Approximations were subsequently employed, largely owing to the Didot point's unwieldy conversion to metric units (the divisor of its conversion ratio has the prime factorization of Template:Gaps).
In 1878, Hermann Berthold defined 798 points as being equal to 30 cm, or 2660 points equalling 1 meter: that gives around Template:Val to the point.<ref name="Smalian1899">Template:Cite journal</ref><ref name="Brekle1994">Template:Cite book</ref><ref name="Funke1998">Template:Cite book</ref><ref name="Blana1999">Template:Cite book</ref> A more precise number, Template:Val, sometimes is given;<ref name="Brekle1994" /> this is used by TeX as the <syntaxhighlight lang="text" class="" style="" inline="1">dd</syntaxhighlight> unit. This has become the standard in Germany<ref name="DIN 16507-1" /> and Central and Eastern Europe.<ref name="GOST 3489.1-71">Template:Cite book</ref> This size is still mentioned in the technical regulations of the Eurasian Economic Union.<ref>Template:In lang Статья 8. Пункт 11. // ТР ТС 007/2011. Требования безопасности издательской (книжной и журнальной) продукции, школьно-письменных принадлежностей.</ref>
Metric pointsEdit
pdfTEX, but not plain TeX or LaTeX, also supports a new Didot point (nd) at Template:Frac mm or Template:Val and refers to a not further specified 1978 redefinition for it.
Template:Anchor The French National Print Office adopted a point of Template:Frac mm or Template:Val in about 1810 and continues to use this measurement today (though "recalibrated" to Template:Val).<ref name="Mosley1997">Template:Cite journal</ref><ref name="Bulletin du bibliophile">Template:Cite book</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Japanese<ref name="JIS">JIS X 4052:2000, JIS Z 8125:2004</ref> and German<ref name="DIN 16507-2" /><ref name="Brekle1994" /><ref name="Blana1999" /> standardization bodies instead opted for a metric typographic base measure of exactly Template:Frac mm or Template:Val, which is sometimes referred to as the quart in Japan. The symbol Q is used in Japanese after the initial letter of quarter millimeter. Due to demand by Japanese typesetters, CSS adopted Q in 2015.<ref name="CSS-Q">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
ISO 128 specifies preferred line thicknesses for technical drawings and ISO 9175 specifies respective pens. The steps between nominal sizes are based on a factor of √2 ≈ 1.414 in order to match ISO 216 paper sizes. Since the set of sizes includes thicknesses of 0.1 mm, 0.5 mm, 1 mm and 2 mm, there is also one of 0.35 mm which is almost exactly 1 pica point. In other words, 2−1.5 mm = Template:Frac mm approximates an English typographic point rather well.
American pointsEdit
The basic unit of measurements in American typography was the pica,<ref name="LegrosGrant1916">Template:Cite book</ref><ref name="De Vinne">Template:Cite book</ref><ref name="Hyde1920">Template:Cite book</ref> usually approximated as one sixth of an inch, but the exact size was not standardized, and various type foundries had been using their own.<ref name="LegrosGrant1916" />
During and after the American Revolutionary War, Benjamin Franklin was sent as commissioner (Ambassador) for the United States to France from December 1776 to 1785.<ref>Benjamin Franklin papers, Kislak Center for Special Collections, Rare Books and Manuscripts, University of Pennsylvania</ref> While living there he had close contact with the Fournier family, including the father and Pierre Simon Fournier. Franklin wanted to teach his grandson Benjamin Franklin Bache about printing and typefounding, and arranged for him to be trained by Francois Ambroise Didot. Franklin then imported French typefounding equipment to Philadelphia to help Bache set up a type-foundry. Around 1790, Bache published a specimen sheet with some Fournier types.<ref>Updike, I, p. 257, II pp. 152-3</ref><ref>Allen Huet, Fournier the compleat typographer, 1972, London, Frederik Muller Ltd, page 3, 4, 62, 63</ref> After the death of Franklin, the matrices and the Fournier mould were acquired by Binny and Ronaldson, the first permanent type-foundry in America. Successive mergers and acquisitions in 1833, 1860 and 1897 saw the company eventually become known as MacKellar, Smith & Jordan. The Fournier cicero mould was used by them to cast pica-sized type.
Template:Anchor Nelson Hawks proposed, like Fournier, to divide one American inch exactly into six picas, and one pica into 12 points. However, this saw an opposition because the majority of foundries had been using picas less than one sixth of an inch. So in 1886, after some examination of various picas, the Type Founders Association of the United States approved the pica of the L. Johnson & Co. foundry of Philadelphia (the "Johnson pica") as the most established.<ref name="De Vinne" /> The Johnson foundry was influential, being America's first and oldest foundry; established as Binny & Ronaldson in 1796, it would go through several names before being the largest of the 23 foundries that would merge in 1892 to form the American Type Founders Co.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The official definition of one pica is Template:Convert, and one point is Template:Convert. That means 6 picas or 72 points constitute Template:Val standard inches. A less precise definition is one pica equals Template:Convert, and one point Template:Convert.<ref name="De Vinne" /><ref name="APL1890">Template:Cite journal</ref> It was also noticed that 83 picas is nearly equal to 35 cm, so the Type Founders Association also suggested using a 35 cm metal rod for measurements, but this was not accepted by every foundry.<ref name="De Vinne" />
This has become known as the American point system.<ref name="De Vinne" /><ref name="APL1890" /> The British foundries accepted this in 1898.
In modern times this size of the point has been approximated as exactly Template:Frac (Template:Gaps) of the inch<ref>Template:Cite book</ref> by Donald Knuth for the default unit of his TeX computer typesetting system and is thus sometimes known as the Template:Nowrap, which is 0.Template:Overline mm.
Old English pointsEdit
Although the English Monotype manuals used 1 pica = Template:Convert, their manuals used on the European continent use another definition. There, 1 pica = Template:Cvt, the Old English pica. As a consequence all the tables of measurements in the German, Dutch, French, Polish and all other manuals elsewhere on the European continent for the composition caster and the super-caster are different in quite some details. The Monotype wedges used at the European continent are marked with an extra 'E' behind the set-size: for instance: 5-12E, 1331-15E etc. When working with the E-wedges in the larger sizes, the differences will increase even more.<ref>Template:Cite book</ref>
Desktop publishing pointEdit
The desktop publishing point (DTP point) or PostScript point is defined as Template:Frac or 0.013Template:Overline of an inch, making it equivalent to Template:Frac mm = 0.352Template:Overline mm. Twelve points make up a pica, and six picas make an inch.
This specification was found in the Xerox Interpress language used for its early digital printers and further developed by John Warnock and Charles Geschke when they created Adobe PostScript.Template:Cn It was adopted by Apple Computer as the standard for the display resolution of the original Macintosh desktop computer and the print resolution for the LaserWriter printer.<ref name="tucker"> Template:Cite book </ref>Template:Fv<ref name="spring"> Template:Cite book </ref>Template:Fv
In 1996, it was adopted by W3C for Cascading Stylesheets (CSS) where it was later related at a fixed 3:4 ratio to the pixel (e.g. 12 pt and 16 px are the same in CSS) due to a general (but wrong) assumption of 96 pixel-per-inch screens.Template:Citation needed
Apple pointEdit
Since the advent of high-density "Retina" screens with a much higher resolution than the original 72 dots per inch, Apple's programming environment Xcode sizes GUI elements in points that are scaled automatically to a whole number of physical pixels in order to accommodate for screen size, pixel density and typical viewing distance. This Cocoa point is equivalent to the pixel px unit in CSS, the density-independent pixel dp on Android<ref>{{#invoke:citation/CS1|citation
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Template:AnchorTemplate:Anchor Font sizesEdit
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In lead typecasting, most font sizes commonly used in printing have conventional names that differ by country, language and the type of points used.
Desktop publishing software and word processors intended for office and personal use often have a list of suggested font sizes in their user interface, but they are not named and usually an arbitrary value can be entered manually. Microsoft Word, for instance, suggests every even size between 8 and 28 points and, additionally, 9, 11, 36, 48 and 72 points (the font sizes 36, 48 and 72 equal 3, 4 and 6 picas respectively). While most software nowadays defaults to DTP points, many allow specifying font size in other units of measure (e.g., inches, millimeters, pixels), especially code-based systems such as TeX and CSS.
See alsoEdit
ReferencesEdit
Further readingEdit
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