Is there any kind of time table when or if the Adobe Fonts service will host OTF Variable fonts? I could even ask the same thing regarding OpenType-SVG fonts. Adobe Illustrator, InDesign and Photoshop support those new font standards. Some of the typefaces currently available via Adobe Fonts do have OTF Variable counterparts.
Google Fonts has around a couple dozen or so typefaces with OTF Variable versions. The vast majority only have a single axis slider for weight. Very few have a width axis slider. Their VAR build of Encode Sans has bugs. At any rate Google appears to be embracing the standard.
Variable fonts take me back to the late 1990's when the Postscript Type 1 Multiple Master format was available for Windows & MacOS and TrueType GX for the Mac. There is a number of typefaces Adobe produced in T1 MM format that I'd really like to see re-done in OTF Variable format, those include Penumbra, Nueva and Kepler.
The easy part of this response is that you should assume that the Adobe Fonts service will support OpenType Variable fonts in the future. And the same may be true for OpenType SVG fonts as well.
However, there are a number of “issues” associated with use of both OpenType Variable and OpenType SVG fonts. Some of these issues can be worked around and others are real “blockers” so to speak.
Neither OpenType Variable nor OpenType SVG fonts are natively supported in PDF and can't be natively supported without either an ISO-32000 PDF version update or auxilliary feature addition approved by the ISO TC171/WG8 committee. I don't forsee such an update occurring anytime within the next two years or more.
There are interim workarounds.
In the case of OpenType Variable fonts, the workaround is to create and subset embed within the generated PDF file standard OpenType CFF or TTF fonts corresponding to each “instance” of the variable font referenced in the source document. That is the process currently being used by current Adobe applications when instances (either predefined or custom) of OpenType Variable fonts are used within the corresponding documents and exported/saved to PDF. There are remaining “issues” in terms of such embedded fonts that we expect to be resolved in an upcoming set of product updates. Even then, don't expect to be able to “edit” text in Acrobat using such OpenType Variable fonts in the short to midterm; that will come later.
In the case of OpenType SVG fonts, the workaround is to create and embed within the generated PDF file a standard PDF Type 3 fonts corresponding to the OpenType SVG font. PDF Type 3 fonts have glyph definitions which are PDF object streams which are easily created from the SVG glyph definitions. Again there are still some issues in the generated PDF that we expect to resolve soon and the “edit” text function in Acrobat using OpenType SVG fonts is a way off.
Support for OpenType Variable Fonts in Microsoft Office
This is a major problem. Microsoft Office applications under Windows allows for text entry and edit using OpenType variable fonts. Display works (at least in Word), but creating PDF from these applications (either via Microsoft's “save as PDF” or Acrobat's PDFMaker “save as Adobe PDF” does not yet work. Printing works for some printers and not for others.
For Microsoft Office applications on MacOS, there seem to be major issues in terms of any use of OpenType Variable fonts.
We are working with Microsoft to help identify and fix these problems.
Support for OpenType Variable CFF2 Fonts in Windows
There are actually two flavours of OpenType Variable fonts. OpenType Variable TTF fonts use quadratic outline glyph definitions identical to those used in OpenType TTF (TrueType) fonts. OpenType Variable CFF2 fonts use Bezier outline definitions and hinting derived and improved from those used in OpenType CFF fonts. The OpenType Variable “concept” fonts shipped with recent Adobe Creative Cloud releases are OpenType Variable CFF2 fonts. The problem is that currently use of OpenType Variable CFF2 fonts in non-Adobe Windows 10 applications currently crash Windows's on-screen character rendering. Also such fonts don't properly print with some key printer drivers.
We are working with Microsoft to help identify and fix these problems.
Support for OpenType SVG Fonts in General
One of the major problems is that support for OpenType SVG fonts is anything but universal. Although Adobe applications currently support OpenType SVG fonts, Microsoft applications do not support them. If you reference such fonts, they are treated as if they were plain OpenType CFF or OpenType TTF fonts using the corresponding monochrome fallback glyph definitions (required as part of the OpenType SVG font standard).
Furthermore, web browser support for OpenType SVG fonts is spotty at best even though SVG support itself is integral to HTML5! Chalk this issue up to “politics” – The Safari and Firefox web browsers support OpenType SVG; Chrome and derivatives of same (including the newest versions of Edge don't support OpenType SVG in favor of supporting the “rival” OpenType COLR font specification in which multiple standard glyph definitions each of potentially different colors are overlaid to produce colored glyphs. For some unexplainable reason, the Google Chromium team that develops the underlying web browser rendering engine refuses to even consider OpenType SVG support.
Both OpenType Variable and OpenType SVG fonts are tremendous technologies, but both have some issues that need to be resolved, hopefully within this coming year (2021). I think you will see support for OpenType Variable fonts in the Adobe Fonts service before OpenType SVG simply because the latter involves some bitter intercompany politics.
Thanks for the detailed reply. I was not aware of the technical issues involving PDF, Microsoft applications and web browser support. I think both OpenType Variable and OpenType SVG are impressive technologies. I've purchased a couple or so typefaces that include Variable Fonts (most recently Futura Now when it was on sale). They do add more design flexibility in my sign projects. One hazard: I do have to remember to inspect the letters in outline view to look for any overlaps in letters. Such a thing would be really bad in artwork sent to a vinyl cutter or routing table. The plotter knife or routing bit will cut wherever a path is present. Some Variable Fonts have overlaps in their glyphs while others do not. The Bahnscrift font in Windows is one that does have overlaps.
I hope Microsoft can overcome its issues with Variable Fonts (and OpenType-SVG). Further, it might be nice if Microsoft and Monotype could develop a Variable version of Arial. I'm not a big fan of Arial. But I see so much horrible quality sign designs involving the default Arial typeface. And so many people just squeeze and stretch this typeface to cram it into any visible space. They won't spend a few minutes to set a natively condensed or extended typeface into the layout. It's just "churn and burn." Maybe if there was a Variable version of Arial all the squeezing and stretching of it wouldn't look so awful. But then there's no guarantee sign designers would use the Variable features in a default typeface even if they were available. Industry specific application support is another matter. I have to use applications like Adobe Illustrator for advanced type features in sign designs because none of the sign industry-specific applications (Flexi, SignLab, Gerber Omega, etc) have proper support for OpenType fonts. It's as if they're stuck in the 1990's.