Scott Prentice, chapter webmeister, president of Leximation, and all-around FrameMaker guru, brought us up to date regarding the latest developments in electronic book publication standards. With the current proliferation of portable Internet devices, the savvy tech doc specialist may want to be aware of the issues involved in converting source documents to those that are readable, usable, and attractive on small screens.
The standard is “EPUB,” which Scott prefers to render as “ePub.” It is just another of many eBook formats, such as MOBI, DJVU, PDF, HTML, and TXT, that has evolved through time to meet user needs. ePub specifies the format and structure of the deliverable, much like a CHM, HLP, PDF, or HTML file does, and it requires both an application and a device to render the content for viewing. The underlying format is XHTML and CSS, with all components, such as content, images, and navigation, invoked from a single header file. Digital rights management (DRM) may also be included. The real wonder of it all is that content flows to fit the screen of the device on which it resides (to varying degrees of quality, as we will see later).
The ePub specification is maintained by the International Digital Publishing Forum (IDPF), and ePub 2.0 became an official standard in September 2007. (The original Open eBook standard of 1999 was actually developed for audio files and accessibility.) ePub 2.0.1 is the current stable build, and there is already a 3.0 draft. ePub comprises the following specifications:
Open Publication Structure (OPS): a standard for representing the content of electronic publications
Open Packaging Format (OPF): defines the structure and semantics as well as the mechanism by which OPS components are related
Open Container Format (OCF): (Seriously, Officer! the ePub was closed!) defines the mechanism by which all components of an electronic publication are packaged into a single deliverable (a ZIP archive)
So what are the many advantages, and why care?
The number of dedicated eBook readers is expected to exceed 11 million units by the end of this year, and the ePub format is supported by all readers and applications except the Kindle. A particular advantage of the format, in an age of vanishing trees, is that it is well suited to content that has limited life span — such as those 15-lb. programming manuals that are soooo last week. Rendered by a variety of conversion tools, ePub format works best for linear content, although reference material can use this approach as well.
It’s relatively cheap to provide instant gratification with this format. The user can search, add bookmarks, and annotations, and the content is very portable. But beware the downsides.
Tables more than a couple of columns wide can be disastrous on small screens. Links do not always work. Compliance with the standard varies highly, with no approach fully compliant. Indexes are not supported (although it is possible to create one as a page with links).
And as we noted earlier, renditions vary greatly (and can be truly extraordinary). Scott presented views of three different readers for the same content, and the differences were striking. As you will need tools (hand rendering is possible but not recommended), be sure to test drive a variety of applications to see which does the best job for your target devices. Scott presented an example of a specification document that he had converted, and it was very attractive and usable on both an iPhone and an iPad.
Enough for this overview. Now see the presentation summary that Scott provided and do your own exploration. Then head to the ePub for an ePint and let it all sink in.