Type 1 to OpenType compatibility

One of the things we had kind of left behind in the migration to OpenType was compatibility. More specifically, we renamed all our fonts so that people could use the OpenType versions alongside the old Type 1 versions. Making them deliberately not compatible then freed us to extend kerning, expand the character set a bit, and make other fixes and changes of varying degrees.

But still, people want to know which OpenType fonts match which Type 1 fonts, and what will happen if they take existing documents and replace the old fonts with the new ones (which of course means changing style definitions or using search and replace). Will they get reflow, and how much? First, we did documents about mapping from Type 1 (including multiple master) fonts to OpenType: a short HTML doc for MM to OpenType, and a huge PDF for regular Type 1 to OpenType.

Then, just a couple of weeks ago I finished a long and complicated migration FAQ on compatibility, reflow, and what exactly we changed. I’ve been working on this on and off for months, just as a background task, adding more things as I thought of them. It’s still not perfect – for example, I left out explanations about pi fonts, or at least linking to the pi font readme, which I should have done.

So, I expect I will continue to evolve the migation/compatibility FAQ for a year or two, and I welcome feedback for future revisions. Feel free to post your comments here.

(BTW, everything is linked from our main OpenType page.)

One Response

  1. Darryl Zurn says:

    Sorry to delve back into your old old blog stuff, but I continue to be interested in the Pi font/Unicode text encodings and this piqued my interest when I read the Pi font PDF from this link.I have created about 50 different Pi fonts for my company’s use, showing everything from LCD displays to keypad keys to packaging logos. Most are Type 1 fonts with all the pi characters stuffed into the slots normally used for regular alphabetic characters. Even my OpenType fonts have no good Unicode slots (where’d I put the company logo or the “Prime” key??) so they follow the same pattern of using normal alphabetic slots.And now we are going to be experiencing the big content management system engulfment. All our (InDesign) documents will be chunked and exported as Unicode text as grist for the CMS mill.I considered doing a huge new OpenType monster using the User Area for Unicode. That way we can search all documents that use, for example, the French keypad’s “start/stop” key (“Arrêt/Marche”). Mapping that to a Unicode U+99DA or some such sounds really tempting. But the document conversion would be truly a massive undertaking.I guess I’m just asking for any ideas that people have for this type of retro-fit. Even making new individual fonts that have each glyph in its old legacy slot (a-zA-Z etc) and ADD a reference in random Unicode UA slots. I can see a lifetime of using the Character Palette to get anything else done, so I guess I’m kind of stuck and have to hope for a rational CMS solution here.Darryl Zurn

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Thomas Phinney

Adobe type alumnus (1997–2008), now VP at FontLab, also helped create WebINK at Extensis. Lives in Portland (OR), enjoys board games, movies, and loves spicy food.

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