Unnecessary Kerning Exceptions

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Joined: 25 Apr 2021

Unnecessary Kerning Exceptions

Post by skyrailhighline »

I'm getting a lot of unncessary kerning exceptions, for example, for /V/A all the A*diacritic glyphs are getting their own kerning exceptions e.g, /V/Aacute and so on have their own kerning exceptions with only a few units difference from /V/A.

It seems like Kern On takes into account the space beyond the Cap-Height as part of the spacing alogirthm? I run Kern On and let it re-generate kerning groups.
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Tim Ahrens
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Re: Unnecessary Kerning Exceptions

Post by Tim Ahrens »

Yes, Kern On does take into account the zone above the cap height.

Looking at your examples, giving V against A+diacritics somewhat looser kerning than VA does not seem unreasonable to me.

If an exception has only a few units of difference (at which UPM, btw?) then maybe, instead of “unnecessary”, we should call them low-importance. What’s necessary after all? If Kern On generates low-importance pairs then that means that you have given a rather generous kB limit, and/or have a rather small glyph set.

Keep in mind that Kern On simply fills the given kB with the most sensible kerning it can come up with. If the limit is generous this will include low-importance pairs whereas if the limit is small it will have to omit pairs that you may call “necessary”.

I’d suggest simply not to worry about low-importance pairs. They are not doing any harm. If data size (font file size) is important to you then reduce the kB limit.
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