Problem getting contextual alternatives to work in practice

Complete beginner teaching myself, so please don’t assume I know anything!

So I have my whole alphabet uploaded and got to the stage of looking at CALT. Starting with J, I wanted to get all lowercase letters to fit in under the J’s overhang. I set up a new letter called J.alt, adjusted the right hand spacing and then set up a CALT feature and a class with all the lowercase letters in it that the J.alt should affect.

Testing in Glyphs, this seems to work and the lowercases fit up nicely to the alt capital J. However, it wasn’t working when I tested outside of Glyphs. I thought maybe it was because the J.alt didn’t have a unicode assignment, so I worked out how to do that and just gave it a random, unused code (0011). Still not working.

I’m fairly sure my coding is correct though because if I go in illustrator (window>type>glyphs) my J.alt is there as well as my standard capital J and I can substitute it manually. It just doesn’t automatically change it to a J.alt if a valid lowercase assignment follows it when i’m typing. It doesn’t work in open office either. Also, I have checked in illustrator and the “standard ligatures” and “contextual alternatives” boxes are both checked under “open type”. I am saving as OTF, not TTF. Any help would be greatly appreciated.

Does not support modern font technology.

  1. Did you compile the features in File > Font Info > Features before you exported?
  2. Are you using the Adobe Fonts folder?