Ligature (typography)

In writing and typography, a ligature occurs where two or more letterforms are written or printed as a unit. Generally, ligatures replace characters that occur next to each other when they share common components. A letter with an accent mark is not usually called a ligature, though it would require a separate block of type just as a ligature does. Ligatures are a subset of a more general class of figures called "contextual forms", where the particular shape of a letter depends upon its context, such as surrounding letters or whether or not it appears at the end of a line.

Latin alphabet

Stylistic ligatures

One of the most common ligatures recognizable as such is "fi." Since the dot above a lowercase i interferes with the loop on the lowercase f, when "f" and "i" are printed next to each other, they are combined into a single figure with the dot absorbed into the "f", which appears as "ﬁ" (note that in some fonts this ligature is rendered as "fi", the two characters presented separately). This is just one of a series, which comprises ligatures for "fi", "fj" (represented in English only in fjord, but encountered in Esperanto, Norwegian, and other languages where "j" represents a vocalic or semi-vocalic sound), "fl", "ff", "ffi", and "ffl". Formerly there were the additional members for "fa", "fe", "fo", "fr", "fs", "ft", "fu", "fy", and for the set of "f" followed by a period (full stop), comma, or hyphen, as well as the equivalent set for the doubled "ff", though "fft" was omitted.

More ligatures were developed for italic fonts rather than Roman ones. Fonts in italics used the "Long s" in ligatures for "sh", "sch", "sp", "st" and "sz" (the probable origin of the German esszet - ß) , among others mentioned on this page. There are also examples for the forms "as", "ch", "ck", "nd", "ng", and "ll". And there is one to make the tail for "Q" reach under a "u", though this was also done by kerning or a character for "u" that included a tail sweep beneath it.

One Roman font by the French typefounder Garamond has a small capital ligature Rx for use in prescriptions, short for the Latin word "recipe", meaning "take". The same font has a minuscule "l" linked to a following apostrophe, for use in such French phrases as "l'amour".

The cursive Snell Roundhand has a ligature "o'c" for the single use in the English phrase "o'clock", as its letter "o" has an extended flourish. For use in ordinal numerals in English, the font has raised small minuscules for "nd", "rd", "st", and "th".

A Roman typeface by William Elder had a distinct "ll". He decorated the second "l" with a nib at mean line height to both the left and right, and put it in a ligature so as to not get it confused with an ordinary "l", to which he gave just the nib to the left.

The Requiem Italic by Jonathan Hoefler is probably the only font that has designed the extremely rare fffl ligature, to be used at least in two German words: Sauerstoffflasche (oxygen tank) and Sauerstoffflaschenspüler (oxygen tank cleanser). This same typeface has plenty of other unusual ligatures, such as stfl for "mistflower", cta for "octagon", ttfr for "Gottfried", a German name, tfl for "outflanked", sfy for "satisfying", ctfi for "factfinding", stfi for "Eastfield" and stfj for "Vestfjorden", and many others.

Zuzana Licko's typeface of 1996 called Mrs Eaves comes with very many ligatures, which go beyond the "cky", "gi", "gy" and "tty" found in the italic to playful ones such as a linked "OG". Some unusual combinations are found in Jack Yan's JY Integrity from 1995, including "gr", "gy", "tr", "tu" and "ty" in Roman and italic versions. Stylistic ligatures may become more common with the development of the OpenType technology, which allows automatic substitution of two separately typed letters in certain programs such as Adobe InDesign CS.

Some typefaces primarily intended for signage include ligatures for the minor words in phrasal names of various languages. Examples include "and," "und," "of," "de," "for," and "het," in some presentations of FF Golden Gate Gothic. These ligatures are underlined, tilted, and float above the typographical baseline; they serve to offset major words for this otherwise all-capital typeface.

The German esszett ligature, ß, was derived from the ligature "long s over round s". Even though "long s" ſ has otherwise disappeared form German orthograpy, ß is still considered a ligature, and is replaced by SS in capitalized spelling.

Letters originating as ligatures

The character Æ (æ) when used in the Danish, Norwegian, or Icelandic languages, or Old English, is not a typographical ligature. It is a distinct letter (a vowel) and when alphabetized, it is given a different place in the ordering, rather than coming between "ad" and "af". In modern English orthography, the same character is not considered an independent letter but a spelling variant (encyclopædia vs. encyclopaedia or encyclopedia)

This character derives from its use in Latin, where it is an optional ligature in some words, for example, Æneas. It is still found as a variant printing in English and French, but the trend has recently been towards printing the letters separately. Similarly, the ligature Œ (œ) while normally printed as such in French, can be replaced by its component letters if technical restrictions require it.

The letter ĳ is derived from "II" (double-I), and is considered a distinct letter in Dutch orthography. There is also a digraph which in Welsh would be a letter, but which is not in most lists of accessible characters, the "Ll".

As the letter W is a relatively new addition to the Latin alphabet, the sound was originally written in various ways. In Old English the Runic letter Wynn (Ƿ) was used, but Norman influence forced this character out. Later, two Vs or Us were written together. As seen in old typefaces, originally the two "V's" crossed in the middle. While VV developed into W, the modern Latin letter W is not a true ligature as it represents a different sound from VV/UU. Because it is relatively new, only four major European languages (English, Dutch, German, and Polish) use the letter in native words.

In German orthography, while ß retains the status of a ligature, the umlaut vowels, ä ö ü are independent letters that historically arose from ae, oe, ue ligatures. The uo ligature, ů saw use in Early Modern High German, but it merged with u (e.g. MHG fuosz, EMHG fůß, MHG Fuß "foot"), and survived as a variant for some time until it was discontinued.

The "ring" diacritic in other orthographies (seen, for example, in å) likewise originated as an o-ligature.

Symbols originating as ligatures

Perhaps the most common ligature is the ampersand: "&". This was originally a ligature of 'Et', Latin for 'and'. It has exactly the same use, except for pronunciation, in French, and is used in the English language just as in French. This character comes in many different forms. It is now not considered a ligature, but a logogram (in English, it is pronounced and, not et). Similarly, the Dollar sign, ^*] originated as a ligature but is now a logogram.

Kerning

A ligature is not the only way of changing the appearance on the page. Besides allocating a particular arrangement as a ligature, the relative location of the characters can be altered by kerning, something which has become easier with phototypesetting, and above all, with computer typography. The fonts for both the Macintosh and Microsoft Windows-based computers include a "dotless 'i'", which (aside from its necessity in printing Turkish) facilitates kerning "fi" and "Ti" instead of using a ligature.

History in Western languages

Medieval scribes, writing in Latin, conserved space and increased writing speed by combining characters. For example, in blackletter, letters with right-facing bowls ("b", "o", and "p") and those with left-facing bowls ("c", "e", "o", and "q") would be written with the facing edges of the bowls superimposed. And in many forms of script, characters such as "h," "m", and "n" would have their vertical strokes superimposed. Scribes also added special marks called "scribal abbreviations" to get rid of having to write a whole character "at a stroke". Manuscripts in the fourteenth century, for example, would employ hundreds of such abbreviations.

When printing was invented, typefaces included many of these, now physical, blocks of type called ligatures. This was done not only because cheap paper had not yet been invented, but also in order to emulate the appearance of hand-lettered manuscripts. To do otherwise would have seemed to the readers as being talked down to, as a modern adult would feel when reading: "Ro•ver falls in•to the emp•ty per•am•bu•la•tor." In addition, ligatures were devised to enable typesetters to assemble Latin words quickly: the endings "us" and "is", and "ij" as a stylish medieval form of "ii" were made ligatures, too. There had been no need for special flourishes of the pen for these.

After printing was extended to modern languages, which didn't use scribal abbreviations, and as typesetting became more perfunctory, most of the earlier ligatures fell out of use, even for texts in Latin. One of the very last of these to remain resembled "q3". It had been used for the Latin ending "-quia", as shown here: ^*

However, new ones were added by typefounders for the English language. The standard ones which remain are the "f" series listed above. Another series, quite resembling these, which used the "long s" in place of the "f", disappeared in the nineteenth century. Some fonts also contain a mixed-case "Th" ligature. In the 1920s, some Roman fonts were still being designed with special ligatures for "ct" and "st", ligatures which remain in many italic typefaces, some of which even have one for "sp". (The last two do not use the "long s".) And in the twentieth century, for the single word "fjord", which has entered the English language from Norwegian, the ligature "fj" has come into existence.

It is only recently that computer-based typesetting has encouraged people to start using ligatures again (although "fine art" printers have used them all along). Generally, ligatures work best in typefaces which are derived from calligraphic letterforms. Also useful are contextual forms, such as swash capitals, terminal characters, and so on.

Ligatures in other alphabets

See also Complex Text Layout.

Ligatures are not limited to Latin script. Some forms of the Glagolitic script, used from Middle Ages to the 19th century to write some Slavic languages, have a "boxy" shape that leads to a more frequent use of ligatures. And in the Arabic alphabet, which has a very "fluid" shape, there is usually ligature between every single letter.

A number of ligatures have been employed with the Greek alphabet, in particular a ligature of omicron (Ο) and upsilon (Υ) which later gave rise to one of the letters of the Cyrillic alphabet — see Ou (letter).

Two letters of the Macedonian and Serbian Cyrillic alphabets, lje and nje (љ, њ), were developed in the nineteenth century as ligatures of Cyrillic El and En (л, н) with the soft sign (ь).

Cyrillic ligatures: Љ, Њ, Ы, . Iotified Cyrillic letters are ligatures of the early Cyrillic decimal I and another vowel: ІА (not in Unicode, ancestor of Я), , , , Ю (descended from another ligature, Оу or , an early version of У).

An example of a more general contextual form is the Greek lowercase sigma. When typesetting Greek, the selection of which sigma to use is determined by whether or not the letter occurs at the end of the word. From these particulars derived the rules for the "long s" in Western languages formerly.

Computer typesetting

TeX is an example of a computer typesetting system that makes use of ligatures automatically. The Computer Modern Roman typeface, which is provided with TeX, includes the five common ligatures ff, fi, fl, ffi, and ffl. When TeX finds these letters juxtaposed in the text, it substitutes the appropriate ligature (unless overridden by the typesetter). Some believe that the writer should be able to decide whether to use a ligature or not; others that it is the job of a typesetter.

The OpenType font format includes optional features for associating multiple glyphs with a single glyph, used for ligature substitution. Typesetting software may or may not implement this feature, even if it is explicitly present in the font information. This type of substitution is used mainly for Arabic texts.

This table shows unligatured sets of letters on the left, the corresponding Unicode ligature in the middle column, and the Unicode code points on the right. Provided you are using an operating system and user agent that can handle Unicode, and have the correct Unicode fonts installed, some or all of these will display correctly. See also the provided graphic.

Unicode

Non-Ligature	Ligature	Unicode
Et	&	U+0026
ſs (or ſz)	ß	U+00DF
AE, ae	Æ, æ	U+00E6, U+00C6
OE	Œ, œ, ɶ	U+0152, U+0153, U+276
IJ, ĳ	Ĳ	U+0132, U+0133
Ng, ng	Ŋ, ŋ	U+014A, U+14B
Hv (Hw), hv (hw)	Ƕ, ƕ	U+01F6, U+0195
DŽ, Dž, dž	DŽ, ǅ, ǆ	U+01C4, U+01C5, U+01C6
LJ, Lj, lj	Ǉ, ǈ, ǉ	U+01C7, U+01C8, U+01C9
NJ, Nj, nj	Ǌ, ǋ, ǌ	U+01CA, U+01CB, U+01CC
DZ, Dz, dz	Ǳ, ǲ, ǳ, ʣ	U+01F1, U+01F2, U+01F3, U+02A3
lʒ	ɮ	U+026E
dʒ	ʤ	U+02A4
dʑ	ʥ	U+02A5
ts	ʦ	U+02A6
tʃ	ʧ	U+02A7
tɕ	ʨ	U+02A8
fŋ	ʩ	U+02A9
ls	ʪ	U+02AA
lz	ʫ	U+02AB
ww	ʬ	U+02AC
ue	ᵫ	U+1D6B
ff		U+FB00
fi	ﬁ	U+FB01
fl	ﬂ	U+FB02
ffi		U+FB03
ffl		U+FB04
ſt		U+FB05
st		U+BFB06

External links

Typography

Gourt Home::Gourt :: Ligature (typography)