Ascender Fonts Designer's Toolbox September 2009

Ligatures & Diphthongs

Typographic insights from Steve Matteson

Doctors use ligatures to connect tissue. Musicians use them to connect notes or musical phrases. A diphthong is a hard to describe sound made when pronouncing vowels. But every font with a standard Latin character set has yet another form of ligature and diphthong – what are they and how are they used correctly?

Definitions
Ligature comes from the word ligate or ‘to connect’. Simply put, a ligature is two or more connected letters – most commonly fi and fl. Diphthongs are also connected letters but are specifically vowels – Æ, Œ, æ, oe. These five connected letters are included in the basic Latin1 character set.

The ’f’ ligatures can, and most certainly should, be set as default behavior in applications by selecting this option in paragraph preferences. Diphthongs must be entered manually from the keyboard.

AE or Æ – What’s the Difference?
For Danish and Norwegian the Æ is actually a letter in the alphabet (along with Ø and Å). But for other Latin-based languages the æ is often replaced with just ae (Nebulæ and Archæology become Nebulae and Archaeology).

Œ is found in Latin as well as modern French (œuf – egg and cœur – heart) and is a different pronunciation than oe written as two letters (moelleux – soft).

Ligatures, by contrast, have no effect on pronunciation or meaning. They were created to correct letter fitting problems (figure 2). The lowercase f, which often extends far to the right side, often touches or disturbs the following ascending characters like i or l.

In a serif font, a set of ligatures is usually not really complete without adding double f combinations and additional ascending characters. (figure 3).

Concocted Connections
Ligatures need not be limited to combinations with the letter f. As discussed last month in the article about alternate letters, Gutenberg used ligatures comprised of as many as four connected letters to help give his mechanically printed pages the appearance of handwritten manuscripts (figure 4).

The OpenType font format gives today’s type designers the ability to create additional ligatures in fonts. The ever problematic Th letter combination is fixed in Bertham Pro™ (Th) and bars on tt become attached in Calibri™ (figure 5).

Taken further, the ligature may become more of an ornamental feature than one which simply corrects fitting. Goudy Forum™ Pro, Refrigerator™ Deluxe and Jana Thork™ Pro exemplify the artistic element that ligatures can offer (figure 6).

Historic (quaint) Ligatures
Many text fonts are now including the ligatures ct and stwhich had fallen out of general use by the early 20th Century. Because OpenType allows users to access these two ligatures they are once again seeing use in formal texts, book titles and for documents intended to appear historical (figure 7).

So use ligatures and dipthongs in their appropriate context: as letters of the alphabet, as solutions to fitting problems or as ornamental touches. Your documents will become more professional and artistic as a result.

Next month we’ll dig around for more useful items in the ol’ toolbox : sorts, dingbats, bullets, ornaments and icons.We’ll try to organize them into groups and discuss how to make them easier to use.

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