Multiple Master Kerning

Hello everyone!
I have a question about kerning in multiple master fonts in FontLab.
Lets say you have two separate .vfb fonts representing the extremes of weight.
Now lets say you've kerned both individually and then made a multiple master font via 'blend'.
The new font contains no features or kerning, but if you open a metrics window it seems like some kerning pairs have been retained (while some others have not).
Does anyone know how kerning is dealt with in multiple master fonts? where are the kerning tables stored? is kerning interpolated as well?


  • The font editor should interpolate the kerning.
  • I've never used "Blend". I use the old "Mask-to-Master" techinque and never have any issues with kerning.
  • Blend will produce just that - a blind blend between two typefaces, not MM design, but yes it will interpolate pair-to-pair kerning and will duplicate/copy kerning classes (metric, opentype and etc. also) in the blended new font. So this would do...

    ...on the other hand, I would suggest that you work in MM space entirely, either by using James's "Mask-to-Master" (but load the second font to mask first) or by "Assign new master" (after you have defined new axis, let say wt-"weight"). In MM space I wold double (even triple) check if all my glyph's outlines are structured (to say) correctly after master assignment - are there new points present; do designs interpolate correctly and what can be done to visually improve the resulting designs. And then I would space/kern my design, build up classes and etc. stuff - in this way you could be 99% percent sure that everything will end up "nicely".... after all this very prolonged and unnecessary explanation - my point is that blending fonts is working in blind, I would suggest that you never do that, especially if you are designing a sort of extended/big family (let say more than 3 fonts - as we could agree that really big is something around 7/8 weights expanded over 3/4 widths + italics)....
  • Thanks for your responses, I see that I've been wasting time messing with blends! I was not clear on how exactly to use the whole mask-to-master concept, thanks for the clear explanation.
  • I would add that when you use the mask-to-master approach, make sure you check "Do not add points". This will require you to be rigorous in your outline drawing and point placement, but will eliminate any "surprises". Also once you have the axis set up use the Multiple Master setting in the preferences to change the display in the font window to something between the original axes. THis way any incompatible outlines will be visible in the font window.

  • Thanks James Montalbano, in fact that was a trick I had been using with the blends as well, good to hear its still a valid approach.
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