OpenType at Work | Standard Ligatures
What are ligatures?Ligatures are two or more letters that are connected. These connections can serve different purposes: they can either solve a problem, have an aesthetic function, or be purely ornamental. Five types of ligatures are defined in the OpenType feature list (each OpenType feature is identified by a four-letter abbreviation): Standard Ligatures (liga), Discretionary Ligatures (dlig), Historical Ligatures (hlig), Contextual Ligatures (clig), and Required Ligatures (rlig). The first three are typically activated by the user; clig and rlig work under the hood. This article will cover Standard Ligatures. They were the only ligatures supported in legacy PostScript Type 1 typefaces before the arrival of OpenType—but on a software level, not as a typographic feature.
Collision hazardThe concept of ligatures is commonly explained by showing the letter sequence fi, with the end of the hook on a lowercase f encroaching on, or even colliding with, the tittle over the i. To keep these two elements from clashing, many designers draw a tidy fi combination as a single glyph. They alter the hook on the f so that its end merges with the tittle over the i, and often also connect the cross stroke of the former with the top serif of the latter. The other classic ligature is the fl combination in a serif face, where the hook on the f joins the top serif on the l. Because of the limited amount of slots available in the character set of the legacy PostScript Type 1 font format, only the fi and fl ligatures were included in the typical character set. Whenever they were available, so-called expert fonts offered some extra ligatures, most often ff, ffi, and ffl. However, when you consider all of the possible letter combinations, you quickly realize this is insufficient, and not very logical. For example, the j has the same tittle as the i, but there was rarely an fj ligature for words like fjord. And other letters like b, h, and k have the same top serif sticking out to the left like the l, yet usually had no corresponding ligatures with the f.
Two (or three, or four, or… ) become oneNow that, thanks to the OpenType format, the capacity of fonts has vastly increased, there is virtually no limit to the number of ligatures type designers can include in their fonts. When the Standard Ligatures feature encounters particular letter sequences, it replaces them with the corresponding ligatures. No need to worry about the searchability of your copy. Early implementations of ligature substitution in apps like Illustrator and QuarkXPress replaced a letter sequence with its corresponding ligature, physically altering the word. By contrast, the Standard Ligatures OpenType feature only changes the sequence’s visual representation. Spell-checking will still work correctly, and your text remains searchable.
Fear of commitmentNot every typeface design calls for ligatures. Only when letters like the f have a significant overhang are they necessary. However, even if your typeface design has no real need for ligatures, that doesn’t mean you can’t have fun with them. Cyrus Highsmith, for example, plays with the atypical f that plunges below the baseline in Gasket, alternating a long and a short version in the ff ligatures, and connecting cross strokes but not hooks and tittles. Some designers specifically avoid ligatures, like David Jonathan Ross. He admits he is not a big fan of ligatures and has left them out of several of his typefaces. And while Turnip does have ligatures, it can also operate in non-ligature mode. Ross thinks sometimes ligatures can look finicky, so he decided not to include them in Gimlet. Instead, Gimlet’s f gets narrower as it ascends. Combined with a long serif on the right, this creates more room and minimizes the overhang. Christopher Bergmann, a German writer specializing in type and language, once mentioned to me that there is also a linguistic argument against ligatures, specifically in situations where they incorrectly connect morphemes. Morphemes are the smallest units of meaning in a language. For example, the word offtrack consists of the two morphemes—off and track. However, in the Marcia specimen, the fft ligature visually divides the word into offt and rack. Because rack is also an existing morpheme, this can create confusion. While it may seem trivial in English, this phenomenon can be problematic in languages that have many long compound words, like German. Ligatures have both supporters and detractors, so some typeface designers prefer to leave the choice up to the user. In his revision and expansion of Meno, Richard Lipton offers both options. In light of the shape he drew for the f, Lipton decided to include a comprehensive suite of ligatures. To accommodate users who don’t typically use ligatures, he added a non-kerning alternate f, which is activated with Stylistic Set 3 (SS03). The shortened crossbar and a decrease in overhang improve the appearance of letter pairs with an initial f and make sure the typeface looks great without the need for ligatures.
Dangerous liaisonsConnected scripts are a typeface category where Standard Ligatures can help optimize connections between letters. Just like in handwriting and calligraphy, letters can adopt different shapes to make the best possible transitions to adjacent letters. A typical example is the lowercase o. While most letters connect at the baseline, the outgoing stroke on the o is often situated higher up, at the middle or the top of the letter, so the shape of the succeeding letter needs to change accordingly. There are a number of ways to solve this problem; some designers choose to draw ligatures for common letter combinations to ensure smooth connections. Whether you prefer your ligatures to be self-effacing or exuberant (or even non-existent), typeface designers create them to make your text look cleaner and more balanced, with a steady rhythm and smoother flow. Ultimately it comes down to personal taste. However, we recommend you activate the Standard Ligatures in your text processor or design app before you make a decision. They are a first, easy step to achieving professional-looking typography.
SupportStandard Ligatures are universally supported in all major apps and browsers.
|A hook is the curved extension of the stem in letters like f, j, and J.|
|A tittle is the dot on the lowercase i and j.|
|A glyph is the visual representation of a character, be it a letter, a figure, a punctuation mark, a ligature, or any other alphanumeric character. The capital A and lowercase a are two different glyphs representing two different characters; but if, for example, a capital letter A exists in a standard form and as a swash variant, these are two different glyphs for the same character.|
|A cross stroke is the (usually horizontal) stroke that intersects the stem of letters like f and t.|
|Overhang is the amount any letter extends beyond its expected boundaries. For example, if the hook on the f has a lot of overhang, it will intrude into the space of the subsequent letter.|
|The baseline is the imaginary line on which letters rest.|
Bald Condensed, né Yves Peters, is a Belgian-based rock drummer known for his astute observations on the impact of letterforms in the contemporary culture-sphere. A prolific writer on typography, he has a singular knack for identifying the most obscure typefaces known to man.