Getting Started with EPUB
EPUB is a standard for authoring and distributing digital publications. An EPUB publication is essentially a website that has been compressed into a single file to make it easier to distribute across the web as well as to access for offline reading. The individual files inside an EPUB publication are created using standard web technologies such as HTML. This means that many of the accessibility best practices that apply to websites are also applicable to the design and authoring of EPUB publications.
One of the advantages of EPUB is the format’s support for reflowable text. As the text size is increased, the content will reflow so that images and other media will move along with their related text. This makes EPUB an ideal format for displaying digital publications on smartphones and other mobile devices that have small screens.
Depending on the software used to read the EPUB book, learners can further customize their reading experience by selecting different fonts and adjusting the line spacing, margins, background colors and other display options. They can also use text to speech to support their decoding of the text as well as improve focus while reading.
EPUB 3 introduced support for fixed-layout EPUB publicatons. These are typically used for media-rich content such as graphic novels and comics that require a more precise layout. EPUB 3 also introduced support for MathML (a markup language for displaying math expressions) as well as media overlays (for synchronized text and audio or "read aloud").
How does EPUB compare to PDF?
Like EPUB, PDF (Portable Document Format) is a format for sharing documents and digital books online. Compared to EPUB, which supports reflowable text, PDF is primarily a fixed-layout format. The fixed layout pages of the PDF format make it ideal for complex, image-rich layouts that require precise positioning (e.g. comics, illustrated children’s books, travel and photography books). PDF is also ideal for reports and other documents that may need to be printed.
However, the fixed layout pages of PDF also make it a difficult format to consume on the smaller screens of smartphones. While it is possible for readers to use the magnification features on their devices to zoom into a PDF document, doing so may result in a loss of resolution while introducing significant scrolling.
Distribution and interchange format standard for digital publications and documents.View in glossary
Equipment or system where principal function is creation, conversion, duplication, control, display, interchange, transmission, reception, or broadcast of data.View in glossary
Access for all people, including people with disabilities, to web environments.View in glossary
Artificial production of human speech, using special software and/or hardware.View in glossary
MathML (Mathematical Markup Language)
XML-based markup language used to display mathematical content.View in glossary
Digital form or representation of a sound which may be used for non-visual access to text and images.View in glossary
PDF (Portable Document Format)
Universal computer file type used to exchange and view documents on any computer with Adobe Acrobat or Foxit Reader software installed.View in glossary
PDF and EPUB on Mobile Devices
Where can I find and read EPUB books?
Digital publications in EPUB format can be purchased or downloaded from a variety of sources. While EPUB itself is an open format, some EPUB publications offered for sale may contain Digital Rights Management (DRM). DRM is meant to prevent the unauthorized distribution of copyrighted material. DRM features can take many forms, from requiring a password to open the EPUB file to preventing the copying of the content. DRM can make publications purchased from an online bookstore incompatible with some readers. In some cases DRM may also prevent assistive technologies such as screen readers from working properly.
For electronic textbooks, VitalSource makes many tittles available in EPUB format. It also has more than 5,000 titles in its library that include accessibility metadata. This accessibility metadata provides additional information about the accessibility features the title supports (e.g. alternative text and long descriptions for images, captions for videos, text resizing). Visit the page for Robertson's Introduction to Fire Prevention and select the "Accessible" option for an example of how accessibility metadata is exposed in the VitalSource library.
Commercial online bookstores that use EPUB as their primary format include:
- Book Store is Apple’s online bookstore and can only be accessed through the Books app for iOS devices and the Mac.
- Google Play Books is supported on many Android devices.
- Kobo supports EPUB on many of its ereader devices as well as its cross-platform apps.
You will notice one of the largest book sellers is missing. That’s because Amazon does not use EPUB, but instead relies on its own proprietary formats.
Your local library may also allow you to download EPUB books through the OverDrive or Libby apps. Some of the books may include DRM and can only be read with the free Adobe Digital Editions software, while others are Open EPUB books and can be read on any reader that supports EPUB. Check your local library’s website for additional information on how to sign up for an OverDrive account using your library card number.
Once you have purchased or downloaded an EPUB book, you can select from a number of free readers:
- Adobe Digital Editions (Mac, Windows, iOS, Android)
- Apple Books (Mac, iOS)
- Dolphin EasyReader (Windows, iOS and Android)
- Voice Dream Reader (iOS, Android)
- Moon+ (Android)
Digital Rights Management (DRM)
Authorizing technologies implemented by rights holders and publishers to limit the distribution and use of proprietary content.View in glossary
One or more pieces of descriptive information about data.View in glossary
Alt Tag (alternative text)
Brief description of a single image designed to be read by a screenreader as an alternative to the image.View in glossary
How do I get started with creating my own EPUB materials?
A simple to create an EPUB publication is to use the "export to EPUB" feature available on a number of authoring tools. Using a familiar tool such as Google Docs, authors would go through the following steps:
- Author their content while following accessibility best practices (properly nested headings, descriptive hyperlinks and images with alternative text, to name just a few).
- Perform an accessibility check on the source document to confirm it follows best practices. Google Docs does not currently have its own built-in accessibility checker, but the free Grackle add-on can perform this function.
- Export the EPUB publication by choosing File, Download as, EPUB Publication.
Microsoft Word does not currently include a built-in option for exporting to EPUB, but the DAISY Consortium is working on a plug-in that will provide this functionality soon.
A number of other authoring and conversion tools can create EPUB publications:
- Pages (free, Mac-only)
- iBooks Author (free, Mac-only, only with the EPUB templates in v. 2.3)
- LibreOffice Writer (free, Mac/Windows/Linux)
- Sigil (free, Mac/Windows)
- Pandoc (free, Mac/Windows/Linux)
- Calibre (free, Mac/Windwos/Linux)
- Jutoh (commercial, Mac/Windows)
- Adobe InDesign (commercial, Mac/Windows)
These tools will vary in their support for specific features in the EPUB standard, as well as in their cost and ease of use. Some like Adobe InDesign are professional tools used throughout the publishing industry and have a steep learning curve, while others like Pages are easy to learn but only work on one platform (in this case Apple devices).
As a final step in the authoring workflow, EPUB publications can be checked for conformance to standards using one of the following tools:
- EPUBCheck: checks to make sure the exported or converted EPUB file conforms to the EPUB standard.
- Ace by Daisy: checks to make sure the exported or converted EPUB file conforms to EPUB Accessibility 1.0. Ace by Daisy is a command-line tool, but a graphical interface known as the ACE App is also now available for Windows, Mac and Linux.
Digital Accessible Information System (DAISY)
Technical standard for producing accessible and navigable multimedia documents.View in glossary