A ligature is a character consisting of one or more connecting letters. As in the graphic above, sauerstoffflaschen—the German word for oxygen tank—is the only word to contain the “fffl” ligature. It also contains the decorative “st” ligature. Below are examples of standard and decorative ligatures.
Letter pairs with their associated ligatures in Adobe Caslon Pro
When appropriate, I always use ligatures of well designed fonts for print and screen. Though, sometimes it requires a history lesson…
As many people aren’t familiar with ligatures, their use is often suspect. The use of some ligatures has become so rare that some folks view them as jarring, especially when editing or critiquing designs. Some standard ligatures—letter pairs like fi fl ff—will pass by unnoticed while others (st ct sk sti) may raise flags. Then it’s also possible, when not in edit mode/mood, some skeptics will pass over the more extravagant ligatures unnoticed.
Often, concerns with ligatures are not unfounded. Ligatures can’t be used for everything, so it’s possible to go overboard with them. They can be used in body copy above certain sizes, but rarely should they be used for titles. Letter combinations in ligatures can’t be kerned, so titles using them often suffer from blown spacing.