Apple recently announced that it has adopted the ePUB3 standard. Any day now the rest of the ebook vendors will follow suit and those of us in digital publishing will have to flip the switch and start producing ePUB3-compliant ebooks that pass validation.
It took me a fair amount of time to learn and implement the ePUB2 standard, so just considering this change nearly rendered me paralyzed until I attended two ePUB3 presentations in 2012: The Digital Bindery’s presentation at TOCCON and Matthew Diener and Liz Castro’s presentation at PePCON. At these presentations attendees learned that there doesn’t have to be a vast difference between an ePUB2 ebook and an ePUB3 ebook; in fact, if your content doesn’t call for the bells and whistles of ePUB3, you need not do more than apply the basic ePUB3 specs.
That brings us to the work at hand: When tasked with evaluating the minimum spec changes we’d have to learn and employ to flip the switch from ePUB2 to 3 for our own digital publishing program, I came up with this as my to-do list:
- Replace the toc.ncx with the toc.xhtml (but for now we’ll include both for backwards compatibility with older ereaders)
- Update content.opf:
- Use the .xhtml extension instead of .html (an issue we’ll have to deal with when QA’ing older titles)
… and if you embed fonts keep in mind that now only WOFF and OpenType are supported. That’s right, no more TrueType, but you can use a font converter.
This is my to-do list to test this week. I have an existing ePUB2 file that I’ll amend with these new specs and validate, validate, validate. I’ll update this post with the results … as well as any adjustments I had to make during testing. I share this in the spirit of giving back to the #eprdctn community, but keep in mind that I’m still learning and can’t help with troubleshooting answers regarding ePUB3, except I can always commiserate! And keep in mind that there are vendor-specific requirements already existing (iBooks suggests versioning, for instance) and to come.
Off I go to flip that switch on.