In the spirit of this answer, is it possible in LuaLaTeX 0.95 to adjust side-bearing of a single character (for instance by adding a extra side-bearing on the left of this one specific character, thus increasing the effective spacing between this specific one and the character before)?

Edit: I wrongly used the term "kerning" (since microtype names it ExtraKerning) to refer to the effective spacing between two character. I slightly rewrote the question in order to use the terms "side-bearing" and "effective spacing".

  • Check this here tex.stackexchange.com/a/312160/2388 and the other answer to this question. But if you want to change the spacing in relation to every other character you should probably better change the bounding box of the glyph itself or look at the microtype package. Mar 7, 2017 at 15:31
  • @UlrikeFischer: Yes, I want to change the spacing in relation to every other character. microtype has the option \SetExtraKerning I would need, but don't handle kerning (yet) in LuaTeX. Mar 7, 2017 at 15:58
  • @UlrikeFischer: Your answer is unfortunately not usefull neither, since font ranges are not (yet) implemented. Mar 7, 2017 at 16:06
  • 2
    Ah ok. Then check the code in frenchb.ldf. It contains lua-code to add "kerning" around punctuation. See \def\activate@luatexpunct{ Mar 7, 2017 at 16:13
  • Sorry. Somebody will be able to help, but not me. If it was a traditional TeX font, that would be different. But TFM it is not ....
    – cfr
    Mar 19, 2017 at 2:13

1 Answer 1


I haven't used it in a while, but fontspec used to have a font feature file.

\setmainfont[FeatureFile=test.fea]{Minion Pro}

test.fea could look like this

languagesystem DFLT dflt;
languagesystem latn dflt;
feature kern {
    pos quoteright period 20;
    pos quoteright comma 20;
    pos quoteright semicolon 20;
    pos dblquoteleft \V -20;
} kern;

to adjust the kerning for the specified pairs.

  • Correct. But I do not want kerning for specific pairs, but for a specific character! Mar 15, 2017 at 18:59
  • 1
    It is it called „kerning pairs“ for a reason. In digital typography, kerning is applied to letter pairs. With True Type Fonts we had „kerning tables“ were the values fo each pair could be found. But with OTF and Unicode this is not feasible any more.
    – uli
    Mar 15, 2017 at 19:42
  • Look at this specific point in the OpenType Feature File Specification and look at the comments from @UlrikeFischer. Mar 15, 2017 at 19:59
  • @Kyle_the_hacker That point (if you mean the first one) is not about kerning but side-bearings, which was perhaps already suggested above concerning changing the bounding box, which I think might amount to doing the same thing.
    – cfr
    Mar 18, 2017 at 23:54
  • @cfr Sorry, English is not my mother tongue. It is indeed named side-bearings. How do I change the side-bearing of a single char? Mar 19, 2017 at 2:08

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