# [luatex] Kerning: when does it not work?

Paul Isambert zappathustra at free.fr
Tue May 3 13:44:27 CEST 2011

```
Le 03/05/2011 10:15, Heilmann, Till A. a écrit
> Reading Paul's answer, I realize that the technical workings of font kerns are more complex than I thought. From a layman's perspective, though, fixing the issue of suppressed kerns on the most fundamental level possible (if that is possible) and offering a "transparent" solution to users would probably be best: It would, therefore, be great if adjustments to pair kerning made in OTF feature files (or by any other means) simply worked "out of the box" and like expected for every instance of the respective glyph pair.

That should be the case when Taco implements it. So rejoice!

> Paul: I must confess that I do not really understand how your experimental code works and how I am supposed to use it. Simply pasting it into the preamble of the sample document I posted earlier didn't change anything (well, I did not expect it to be that simple, either). For my real-life book project I load fonts like this:
>
> [...]

I'm not a LaTeX user; the code was tested with plain TeX and worked well
on so simple an example as ``V\penalty1000 e''. I thought pasting it in
a LaTeX preamble (preferably at the end) would work, but somebody with
knowledge in LaTeX should probably take over here...

> In the text I "call" these different fonts with the usual commands for families (\rmfamily, \sffamily, \ttfamily), series and weights (\mdseries, \bfseries), and sizes (\fontsize{}{}). I am reluctant to change this because the fontspec and unicode-math packages work just fine for me and do a lot of nice things like scaling that I would not know how to achieve otherwise.

Such font loading shouldn't be relevant to the issue. Provided the issue
is, indeed, kerns prevented by penalties, which is the only thing my
code is meant to fix.

I'll make some experiments with your original document and try to see
what's wrong.

Best,
Paul
```