If Fontlab isn't interpolating spacing and kerning values in instances you have done something incorrectly. Either that or your masters have matching values.

OK. It does interpolate sidebearing values, but it just deletes all kerning pairs from the instance. Any idea what I'm doing wrong?

I know my spacing values are messy and don't make much sense, but that shouldn't stop Fontlab from interpolating kerning values.

I'm not sure why your kerning pair has been removed but I wouldn't trust the interpolated kerning too much from a Fontlab MM file. In the past - previous to Superpolator - I've found the desired instance via MM and then done a straight blend (not MM) to have some better kerning to start with. Superpolator does a super job with kern pairs if you're wondering.

Superpolator does a super job with kern pairs if you're wondering.

I've found that Superpolator is that answer to all my Fontlab interpolation problems. And I have been told that Glyphs also handles everything quite well.

And if you're handy with Python the Robofab site explains how to just interpolate directly between two fonts with a script.

I don't know what you are doing wrong Jasper, but I have never had a problem with FontLab interpolating side bearings and kerning data. But then I use that really old Mask-to-Master process rather than the Blend Fonts.

I think of what I do in FL as master to master. I that the mask to master process you speak of here? Or is there yet a 3rd way? Blend fonts is definitely different.

I have superpolator now though. I think that will take over.

-e.

I used 'blend fonts'. But I guess I'm just gonna buy superpolator.