Hi there
When I export my font to variable TTF my “Optical Size” doesn’t work.
It works in my interporlation preview (within Glyphs), but not when I have exported.
I have checked everything, but can’t find the error.
So it might be an export error or just a file setup, which I can’t see.
This is my setting:
In which app did you test and how?
I have tested in these two:
I can recommend using FontGoggles instead of browsers. Neater, less unknowns, and you can save the documents and colour the files with appropriate Finder tags.
Then you should also use FontTableViewer. Drop your generated VF-TTFs (and any other format for that matter), and look at the fvar table. It should contain your axes.
Thanks! I got it working 
There used to be a bug in Safari misinterpreting the opsz axis. Not sure if it still manifests itself. More details in the variable font tutorial.
Thanks. I found out there also was a Safari problem on the ‘Optical Size’ property.
The problem is that if you use text-rendering: optimizeLegibility; and -webkit-font-smoothing: antialiased; Safari will handle Optical Size for you and you will be unable to set that. So if you want to set optical size on a variable font, leave these CSS values unset.
Safari is the new Internet Explorer. A pain to work with. The bugs aren’t even the same across MacOS, iOS, iPadOS.
