Two or more letters combined into one character make a ligature. In typography some ligatures represent specific sounds or words such as the AE or æ diphthong ligature. Other ligatures are primarily to make type more attractive on the page such as the fl and fi ligatures. In most cases, a ligature is only available in extended characters sets or special expert sets of non-OpenType fonts. Newer OpenType fonts frequently have the extended characters included but not all fonts contain all possible ligatures.
Ligatures used to improve the appearance of type are usually character pairs or triplets that have features that tend to overlap when used together. The ligature creates a smoother transition or connection between characters by connecting crossbars, removing dots over the i, or otherwise altering the shape of the characters.
- Standard ligatures may include fi, fl, ff, ffi, ffl, ft. The purpose of these ligatures is to make certain letter parts that tend to knock up against each other more attractive.
- Discretionary ligatures may include ct, fs, st, sp. They tend to be more decorative in nature and often lend an Old World or old-fashioned look to text.
- Unusual or Uncommon ligatures might be included as standard or discretionary and include combinations such as fj, fk, ij, and many others that are less commonly used.
- Long s ligatures are typically discretionary ligatures found in some fonts. The long s looks like an f missing the right side of its crossbar. This long s is combined with h, l, i, t, or another s to form ligatures common in some 18th century writing. When trying to recreate an authentic 18th century document you may need these long s ligatures — which have some special usage rules.
Accessing Ligatures in SoftwareLigatures can be turned off and on in the Text, Type, or OpenType menus of page layout software. In some cases you may have the option of using only the standard ligatures or both the standard and discretionary ligatures found in a font. With this feature turned on you all you do is type the letters (such as fi) and it will automatically be replaced with the appropriate ligature if available in that font. Alternately, you can turn off ligatures and insert ligatures only in certain places (such as by copy and paste from Windows Character Map).
In some rare cases a font might include a standard ligature that another font designates as discretionary. This can cause some problems if you want to turn on standard ligatures in your software but don't want that normally discretionary one to show up.
They may appear to be a single character but each letter is editable. If you want to change fine (with fi ligature) to Fine you only need to change the f to a capital letter. The i will convert to the dotted form. When using ligatures, changing the tracking may have no effect on the spacing of the individual parts of the ligature, resulting in odd spacing. However, in some programs if the tracking becomes extreme enough the program may replace the ligature with normal characters.