One TTF becomes larger in file size?

I’m making five TTF’s. Manually hinted (Y-direction) from FontLab. It’s a typeface in five weights, interpolated, so the outlines are identical.

Everything was fine, until I manually added some new glyphs to all fonts, from another source document.  I copy/pasted these new glyphs, about . After that, one of the fonts became 100K instead of 70K upon export.

All five fonts share same classes, features, components, number of kerning pairs etc and I’m using the same settings to export them too.

What could possibly be the issue with that one single font? I’m totally stuck. Any ideas?


  • It could be a number of things, decomposed composites, VDMX or LTSH tables added, a different glyph order increasing the size of the cmap table.

    What you need in is a tool that can show you the tables in the font and the size of each table so that you can do a comparison of before and after.

    You could try TTX/FontTools to give you some detailed info of what is going on in each table of the fonts.

    A tool that does comparisons of two or more font files is a valuable tool which many foundries will have, and is often written in-house to suit their own work practices.
  • OTMaster helps a lot with this issues.
  • The free OTM 3.7 Light version (Mac OS, Windows, Linux) will be sufficient for this purpose, I reckon.
  • Feel free to send ’em over, mate. I’ll have a look.
  • Hi Goran, ¿are you exporting from Glyphs? if Yes, ¿the problem appears from the very first export, or only after you hint it and re-export from Fontlab?
  • Thanks! I’ll try OTM and see what could be the issue — and maybe learn something. If that does not help I’m definitely getting in touch with you Christoph (thanks for the offer!).

    Originally the document comes from Glyphs, but this happens after re-export from FontLab. On one font only.
  • We have just made a 'cut-down' version of one of our in-house tools to give a visual comparison of font tables. It's a simple 'one trick pony' called Font Table Compare which you can get here:
    Available for Mac and Win...and free.
  • Thanks, I’ll give it a go!
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