How do I disable ligatures?

Question

I am writing my dissertation in LaTeX I am faced with this odd situation that if 'f' character has another character (f, i or l) next to it, it sticks the two together as can be noted below. This makes the two 'f' look different.

How can I disable this?

Answer 1

Ligatures are generally considered a good thing, but if you really want to disable them and are using pdfLaTeX (or LuaLaTeX^†), the microtype package can do this for you. If you load this package and add \DisableLigatures{encoding = *, family = * } to your preamble, all ligatures will disappear from your output.

Here's an example (pdfLaTeX only):

\documentclass{article}

\usepackage{microtype}
\DisableLigatures{encoding = *, family = *}
% \DisableLigatures[f]{encoding = *, family = *} %% <- only disables f-ligatures

\begin{document}

Different -- without ligatures!

\end{document}

Note that the double hyphen (--), which is normally typeset as a single en dash, is also treated as a ligature by TeX and that this is suppressed as well. The standard set of ligatures that TeX recognises consists of:

Actual ligatures: ff → ff     fi → fi     fl → fl     ffi → ffi    ffl → ffl
"Fake" ligatures: -- → –    --- → —     `` → “      ’’ → ”      !` → ¡     ?` → ¿

You can use \DisableLigatures[f]{encoding = *, family = * } to only disable ligatures that start with the letter f (i.e., the entire top row).

The microtype package actually does a lot more than this. It implements a number of micro-typographical features that generally improve the layout of your paragraphs. (See the documentation for more information.)

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^†To make this work with LuaLaTeX you need to also use the fontspec package and supply the Renderer=Basic option while loading your font. For LuaLaTeX, Mico's answer is therefore preferable.

Answer 2

From Buttericks Practical Typography:

Lig­a­tures were in­vented to solve a prac­ti­cal type­set­ting prob­lem. In the days of metal fonts, cer­tain char­ac­ters had fea­tures that phys­i­cally col­lided with other char­ac­ters. To fix this, font mak­ers in­cluded lig­a­tures with their fonts, which com­bined the trou­ble­some let­ters into one piece of type.

These are the examples:

However, not all fonts have the ff ligature with both letters fused, so if you do not like them, the best that you can do is to choose another font. In the Latex font catalogue every font has a section Ligatures and German double s, where you can see how they will be displayed.

For instance:

Bookman:

Cochineal:

Garamond:

Didot:

Font without ligatures:

New TXTT:

Letter Gothic

Note: I do not know an easy way to find a font without ligatures, we open it and look for absence of the Ligature section.

Answer 3

Ligatures are a feature of superior typography!

However, there are cases where good typography indeed calls for suppressing them, especially in German texts: at word-seams (German: Wortfuge).

With package babel and the ngerman option, ligatures are suppressed using "|

For example Auf"|lage, auf"|finden, auf"|fangen, schlaf"|los.

As stated in Mico's comment a number of English words also call for suppressing f ligatures. Here, this is accomplished through \/:

shelf\/ful, self\/less, half\/line, ...

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But again, keep ligatures in different, affordable etc.

Answer 4

If you absolutely must suppress ligatures (not a good idea, but since you insist...) and if you happen to use either XeLaTeX or LuaLaTeX to compile your LaTeX document, you could achieve your typesetting objective by specifying the option Ligatures=NoCommon while executing \setmainfont, \setsansfont, etc. Alternatively, run \defaultfontfeatures{Ligatures=NoCommon} before running \setmainfont and \setsansfont.

Aside: This method will not keep -- and --- from being made into en-dashes and em-dashes, respectively.

A final comment: Do learn not to only tolerate, but to actually appreciate and like typographic ligatures. They're your friends -- typographically speaking.

\documentclass{article} 
\usepackage{fontspec}
\defaultfontfeatures{Ligatures=NoCommon}
\setmainfont{Latin Modern Roman}
\setsansfont{Myriad Pro}[Scale=MatchLowercase]
\newcommand\blurb{off fit fly office baffle}
\begin{document}
\blurb

\textbf{\blurb}

\sffamily
\blurb

\textbf{\blurb}
\end{document}

Answer 5

For those who just want to disable only one place (e.g. inside some links). You can try to use T\/h, f\/i, which will avoid combining the characters together.