[anorakoverflow]

The author's point about "dumb" ligatures doesn't really hold up: While the "fi" ligature will always mean "f followed by i" its use is not always correct.

For example, in German compound nouns, you do not set a ligature between the two nouns. For instance, "Kaufläche" (Kau: chewing, + Fläche: area) should be written with ligature, while in "Kaufleute" (Kauf: purchase, + Leute: people, = merchants) the ligature should be avoided.

[crazygringo]

Wow, that's fascinating -- do you have a reference for that? I'd love to learn more, especially as to why -- it seems like that would just result in ugly typography. Or is it solely about the bar of the initial "f" connecting to the next letter?

[Johnny_Brahms]

Well, typography is often about readability. Removing the word boundary in compound nouns isn't really helpful since it removes a boundary that conveys meaning.

There were some examples of nouns where you should avoid ligatures in the TeX docs iirc. Shelfful and selffullfilling are the only ones I remember.

In German (every single fff on any page that bothers to set their own fancy-pants font) and swedish text you see it all the time, often coming from self-proclaimed typesetting/font nerds.

[rocqua]

Are there any font specifications that allow for this kind of distinction?

[mrob]

Every font with ligatures allows for this, because they also include glyphs for the component parts of the ligatures. It's the responsibility of the typesetting software to enable or disable ligatures as required, eg. with this TeX package for selective suppression of ligatures:

https://www.ctan.org/pkg/selnolig?lang=en