Help with font validation error when exporting to .epub

[steve_4231]

I'm uploading an .epub file to IngramSpark and—on the surface—everything looks to be fine. However, I'm served with this error message (three times) from IS:

(PKG-026): /META-INF/encryption.xml: Obfuscated resource must be a Font Core Media Type (was declared as "application/x-font-ttf" in "OEBPS/content.opf").

I assume this is in relation to the 3x fonts I'm using in the .indd file – however, they are all Times New Roman (Regular, Italics and Bold styles) so there shouldn't be a licensing issue. They are .ttf files so I'm assuming that's the issue, but how do I go about rectifying that?

[Laura Brady]

This is a dumb error that's not really an error at all. Basically EPUB Checker doesn't like TTF fonts. You can fix this by changing the media type in the OPF on thost true type fonts.

Change it from: media-type="application/x-font-ttf"

to: media-type="application/vnd.ms-opentype"

I hope that helps.

[James Gifford—NitroPress]

Don't embed fonts for reflowable EPUB. It's an obsolete practice.

(As is editing generated EPUBs; if you have to perform surgery on it, you didn't generate it right. 🙂 )

[Laura Brady]

That's bananas, James. Developers should embed fonts as they see fit, of course. The end user may change the typeface, but that's their perogative. 

And if you aren't editing the EPUBs you create from InDesign, they you aren't paying attention to accessibility or clean code. 

[James Gifford—NitroPress]

Sorry. We come at the field from wholly different perspectives, and mine is that of professional publication — which among other things does not include the notion that "anything a designer wants to do is fine." That doesn't apply in print or any other area of book/publication design, and it doesn't apply in digital publication either.

And embedding fonts like Times Roman is just... ridiculous. Bad enough when it "has" to be some fantasy or high-art font, but whitebread, vanilla fonts? Just file bloat and technical complications, besides the fundamental rule — to me — of not respecting the medium.

I haven't edited an EPUB in a decade. It is absolute not a necessary or (any longer) useful step; the correct approach is to get the document and export optimal for export in the first place.