How to display Adobe fonts in reflowable ePUB for end users in Kindle

Report · Feb 04, 2023

There are multiple layers to my question. I have scoured Google for this, but no clear answer has come up about my specific situation, as most answers pertain to fixed layout epubs—and Adobe Support is rather vague. I need this explained to me in layman's terms please.

Is there a way to display specialty (otf) fonts as they should correctly display in KDP? Removing obfuscation entirely seems to be the only way they show up in KDP (Adobe and IDPF's obfuscation does not work), and keeping obfuscation falls back to their Baskerville font.
Is de-obfuscating allowable if you have an Adobe Fonts account?
Is de-obfuscating end-user protected?
If keeping obfuscation is the only way to go about this, is it even possible to display the font at all? If so, what component am I missing?

I have seen multiple ebooks display featured fonts in Kindle without me having to download fonts to the device. Furthermore, I have seen other book formatting agencies use specialty fonts via Kindle. So, I'm wondering if leaving the font obfuscated strips the font on my end but maybe it will show in the published (purchased) version? This would be vital information to my clients, so any advice would help.

Some background: I format my work for my author clients with Adobe Fonts and use ID to convert my reflowable epubs to Sigil. Thank you in advance.

Report · Feb 04, 2023

The short answer is that specifying/embedding fonts in reflowable EPUB (and thus Kindle) is a poor practice, and it often presents several technical hurdles, not all of which can be easily overcome.

That Adobe fonts are somewhat more tightly controlled than most, especially within the Adobe app ecosystem, doesn't help.

My sincere recommendation is that e-books, especially to the very closed and controlled Kindle platform, should not use specified fonts. The readers, again especially Kindle, really want full control of font, size, spacing etc. at the user's direction, and trying to impose a print-like format on this model is difficult, unreliable and contrary to the spirit of the medium.

Report · Feb 04, 2023

Thanks for the advice! I am still left scratching my head, though, because it seems like it's possible, and I can't seem to find a clear-cut answer.

In Response To The Goth Editor · Feb 04, 2023

As far as I know, Adobe fonts are embedded in PDFs and EPUB s and saved on the computer in a hidden folder. They get encrypted names with a leading dot to make them invisible.

In Response To The Goth Editor · Feb 05, 2023

It can be done, even with Adobe fonts.
It is fussy and difficult to override the export preferences and get specified fonts into the right places of an EPUB.
It is then a crapshoot as to whether any reader (specific app, and then as-implemented by a user, and then consistently) will honor the font specs and not use any of its many preferences to revert to system fonts, if it doesn't just make a mess of the display trying.
Embedding fonts also bulks up EPUB file size somewhere between "considerably" and "enormously," which is in no way a good thing.

It's not that there is some secret only the pros or commercial houses know, other than an understanding of what's something of a tightrope walk to get the least-glitchy, most-compatible result. At a minimum, it's a careful adaptation of font use to the layout, limiting certain choices and compromising the result, just for the trivial win of using a specific font. And even then, any reader out there may decide its base system font is a better choice.

You can do amazing things with just a serif and sans-serif font, each with four faces, and judicious use of simple graphics and color. Getting bound up on the idea that a specific font or fonts are needed is just... the wrong road for e-books, and making the mistake of viewing a rich medium through the limitations of print.

If you must have a print layout, with fonts — use PDF. 🙂

Report · Feb 05, 2023

You say there's a way to do it, and I don't mind learning to wrangle the fussy part if that means my client can feature a fancy chapter header in their epubs. I don't bother with main text, just the chapter headers.

This makes me wonder if subsetting while de-obfuscating the featured chapter header font would be the way to go, then, because that also reduces the file size. Perhaps this is turning more into a legal question since Adobe states "any ebook authoring workflow which requires the user to move the font files themselves is not allowed under the Terms of Use," but I don't ever require my clients to move the font files; I just give them the epub file, and they turn around and publish it.

Report · Feb 05, 2023

Adobe Fonts - the subscription service - provide only activated fonts in Windows/Mac, and web fonts via specific HTML (and on Adobe's servers). Nothing else at all. You don't receive any font files (or if you happen to find them, doing anything with them is a breach of the license).

(I have no knowledge on the Kindle question, sorry).

In Response To Test Screen Name · Feb 05, 2023

The fonts are absolutely licensed to be embedded. Whether the reader app can take advantage of them is a whole different thing, I agree with @James Gifford—NitroPress on this...don't bother trying. Some apps may honor it for the initial display but ultimately it's the user that has control over it.

There are too many users that need to distance themselves from print and work within the rules and the spirit of the medium.

Report · Feb 05, 2023

A shot in the dark, here, since you aren't very clear on where the problem occurs (or even exactly what the problem is).

When licensed fonts are embedded into a PDF or EPUB, they are encrypted and bound to that document so that they cannot be extracted and re-used. (Maybe this is what you mean by obfuscation.)

Since the encryption is tied to the document, it's possible that hacking at the doc in Sigil is breaking the connection and leaving the doc unable to decrypt the fonts on the fly, meaning it can't use them.

If that doesn't sound right, some more clarity on exactly what problem you're encountering, and at what point beween ID and Kindle, would help.

FWIW, I am strongly against editing EPUBs or workflows that depend on "fixing" an ID export using any post-export tools. If this is indeed Sigil mucking up the embedded fonts... another point to my dislike for the approach.

If you insist on specifying the fonts and don't want to try and fix this licensing/encryption issue at the export stage, you could substitute generic, free-license fonts in place of the Adobe ones. There are close analogues, if not more or less identical ones, for most of the common book fonts.

Report · Feb 05, 2023

Just saw this! I just posted to your comment!

Report · Feb 05, 2023

The issue: embedded, obfuscated fonts in the epub default to KDP's Bookerly font inside of Kindle Previewer. The only way those fonts show as they should is if I completely remove the obfuscation in Sigil and set it to none. Once I do that, the fonts show up beautifully in Kindle Previewer.

I have tested the files in Pagina's Epub Checker, and they all come out valid, even after I've de-obfuscated the featured font.

This is what leads me to question if removing obfuscation is okay to do and to then hand to my clients, since I'm not asking them to "move" or do anything with the font files themselves. I've read subsetting could be a good choice, since it removes unused characters from the file, therefore rendering it useless if the fonts are actually used outside of the epub after I've given it to my clients.

Adobe is not super clear on this, thus my four-layered question.

Sorry for the double comment. We can condense them into one next time you reply.

In Response To The Goth Editor · Feb 06, 2023

If everything works with the font encryption removed after export... it all comes down to whether you want to respect the Adobe licensing agreement for fonts, which I think most of us here would recommend, but is one solution.

Substituting free fonts for the Adobe ones would seem to solve both problems.

I've only done a little work in the direction of (1) embedding (2) Adobe fonts in EPUB, but have never run into the errors and problems you're reporting.

I still think the culprit is mucking with the EPUB file in Sigil, after export from InDesign. Try this: pass the unmodified export file to Kindle Previewer and see if the fonts work as intended, without errors, regardless of whether the book has the formatting you want.

You should always subset embedded fonts. It vastly reduces file size in most cases.

Report · Feb 08, 2023

Thank you, James. No luck with your suggestion. Exporting to a reflowable epub and viewing it in Kindle just displays their Bookerly font. I see a ton of conflicting information on other forums, and they don't really ever come to a solid conclusion.

Upon doing more digging, I think I may have found my answer.

My current @Blissful_help0D4E-face coding looked like this with removing obfuscation in order for Kindle Previewer to display it:

@Blissful_help0D4E-face {
font-family:"Bree Serif";
font-style:normal;
font-weight:normal;
src : url("../font/BreeSerif.otf");
}

However, when I changed it to (the single quotes vs the double quotes), it showed up in KP with only the IDPF method obfuscation, not Adobe's method:

@Blissful_help0D4E-face {
font-family:'Bree Serif';
font-style:normal;
font-weight:normal;
src : url(../font/BreeSerif.otf);
}

All of this success made me want to jump with joy, BUT this method did not work with a different font my client bought and licensed, so I could not replicate the same outcome with her font. I wonder if it only pertains to Adobe fonts that I can use this way. So far, two of the fonts listed below meet my ultimate goal of 1) releasing the file without removing obfuscation (phew) and 2) displaying it in KP as it should. However, I also tried to subset the fonts, but only the client's would successfully subset and not Adobe's.

After all this is said and done, I did a test on the following fonts:
"Gonestone Signature" (client's licensed font)

"Bree Serif" (Adobe Cloud font)

"Chainprinter" (Adobe Cloud font)

It goes saying that I would love to also be able to successfully subset these fonts, but I feel like the universe hates me right now haha. I feel like all of this research and testing is two steps forward and three steps back.

In Response To The Goth Editor · Feb 08, 2023

I see a ton of conflicting information on other forums, and they don't really ever come to a solid conclusion.

Yes, well, there are reasons for that. But moving on...

About all I could say here is what I've already said — it's a fraught, uncertain process, the fixes are usually semi-hacks that may not be repeatable on other documents, and in the end, most EPUB readers and Kindle in spades do not like surrendering font and typography control, so the battle never ends.

Put another way, you can keep trying to find rational solutions, but it's not an entirely rational situation... so good luck. 🙂

Report · Feb 08, 2023

Yeah. I clearly refuse to to give up haha! Thank you for your input. 🙂

In Response To The Goth Editor · Feb 08, 2023

I'll just point out that none of those fonts is distinctive enough not to consider reasonable substitutions, and all have free alternatives. (Gonestone is, in fact, a freebie version of the licensed Gunstone.)

So you may want to remove that brick from the wall to start with.

Report · Feb 06, 2024

my fonts appear on kindle after de-obfuscating them using sigil.

I also checked that there were " and not single quote in the calls.

I used an epub checker and I noticed that the version with indesign obfuscated fonts doesn't even pass epub 5.0 standards

when I de-obfuscated I passed all checks and the fonts appear in kindle.

Images of my book in kindle previewer and passing all checks after de-obfuscation

I believe the indesign obfuscation doesn't work with current epub standards, so the remaining choice is to de-obfuscate or not use fonts. ID obfuscation passed all checks through version 4.24 but everything after was non-compliant

In Response To Emerald24601 · Feb 06, 2024

I'll stand by what I've said in every instance of this topic: don't spec or embed fonts in EPUB. It's counterproductive in all ways. (And fonts should never be, nor ever need to be, un-encrypted for validation reasons. The process encrypts them for a reason — a fairly weak, outdated reason, but for a reason.)

As for validators, there's only one validation that has any value: does the file work on either Kindle or a vanilla EPUB reader like Calibre? Everything else is pretty much irrelevant, of importance only when an EPUB is built by hand and all kinds of structural mistakes can be made. InDesign EPUBs can go straight to any but one or two oddball library/sellers without any errors, regardless of whether they tick every validation point. (And there's only one validator worth using for a technical check, EPUBchecker; most others are either that wrapped in a UI or, worse, EPUBchecker wrapped in a UI that then helpfully adds the developer's own notions of what's valid or not.) I don't think I've had a validation pass tell me anything useful, good or bad, with ID exports.

I'm curious where you're getting 'EPUB 5.0 standards' when the turtles on the EPUB commitee seem to think v3.3 is the latest.

Report · Feb 06, 2024

oops the versions are versions of the epubcheck tool from w3

ID obfuscation doesn't work with the current version of the tool

that is the number of the software not epub. correct it is still 3.3

Report · Feb 06, 2024

right clicking the font in sigil lets you change the obfuscation.

I could not get a validation from EPUBcheck in the current version while using the indesign encryption.

de-obfuscating the fonts in sigil allowed them to show up in kindle.

my distributor uses EPUBcheck for validation so I don't have a choice here since I don't want my book to get flagged.

something about ID obfuscation isn't valid for the latest version of EPUBcheck

In Response To Emerald24601 · Feb 06, 2024

something about ID obfuscation isn't valid for the latest version of EPUBcheck

I'll experiment to see what my results are.

However, you're combining at least two situations here: Kindle and some other distributor, who I assume is EPUB-based. Whether the latter is fussy about passing EPUBcheck or not, it is extremely difficult to get designated fonts working in Kindle, regardless of EPUB source or validation. There's a whole chain of issues there, but it comes down to two things:

A professional publisher does not submit docs with unencrypted commercial fonts, no matter how small a technical violation it might seem;

an experienced publisher does not designate fonts in either Kindle or EPUB, since the only real result is to bloat the file sizes, cause all the problems you're seeing and have the choices undone by various readers' programming. Trying to build e-book display around print concepts is an outdated model. Both the readers (hardware and apps) and the users can and will change the font, size, spacing etc. and trying to force their choices generally leads to problems.

E-books should use only the base CSS file designations —serif, sans-serif, monospaced — and neither specify font names nor embed the files.

In Response To Emerald24601 · Feb 06, 2024

I could not get a validation from EPUBcheck in the current version while using the indesign encryption.

Okay, as I expected — EPUBcheck is not giving an error on these fonts; it is issuing a note, an 'info' that they could not be decrypted, which is exactly as it should be. No distributor, no matter how fussy, should consider this a fault.

And in Kindle, the fonts are irrelevant because the user can switch (globally) to any of the reader's base fonts. There's no reason to spec fonts, embed fonts or tear your hair out trying to fix embedded font problems... bypass all of those.

Report · Feb 06, 2024

whelp.... mine just says "failed" which to me means they won't distribute a book with the ID obfuscation. so yeah.... I guess you can't include fonts, at least with my distributor. but de-obfuscation allows them to pass and show up in kindle. I guess it is then a professional / ethical consideration whether to include decrypted fonts in the file.

In Response To Emerald24601 · Feb 06, 2024

Are you using EPUBcheck, directly, as it's released, or some "wrapped" or "improved" version of it? I don't know of a version that says "Failed" among its reporting. It generates a line for every issue, with a ranking of four levels of severity.

Are you aware of how these four levels of validation failure are interpreted? It sounds as if whatever tool you're using is helpfully translating an "info" report (the lowest level and not considered a fault) as a "failure."

Regardless of the detail, the entire issue is only a problem if you insist on embedding fonts. The solution seems obvious, to me. 🙂

Report · Feb 06, 2024

https://www.epubconversion.com/epub-validator/

here is EPUB check 5.0.1 running online.

anything I have tried with InDesign encryption doesn't pass, or perhaps these are all warnings.... (see screenshot) but in any case it gets flagged for me so I can't use it. I was curious so I changed the obfuscation to Adobe and everything passed EPUB check. I opened the same epub (with Adobe encryption) in Kindle previewer and none of the fonts are present. It doesn't seem like In Design's obfuscation is usable at least not with the current version of epub check, though I suppose some places will let you proceed when there are warnings.

Kindle can't read any obfuscated / encrypted fonts and will just ignore all obfuscated fonts and substitute its own. Apple Ibooks can read both Adobe obfuscation and InDesign obfuscation.

Kindle can read included fonts only if they are de-obfuscated.