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6th European eAccessibility Forum
Putting eAccessibility at the core of information systems

26/03/2012, 9:00 - 18:00
Cité des sciences et de l'industrie, Paris

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Printable version

EPUB 3 - ebooks designed for all

Markus Gylling (Sweden)
International Digital Publishing Forum - Daisy

Speaker's information

photo Gylling

Markus GYLLING is the Chief Technology Officer of the IDPF consortium (International Digital Publishing Forum) and the technical director of the DAISY Consortium. Markus has an extensive experience in developing accessibility standards for electronic books, and software tools to support the particular standard DAISY DTBook and the DAISY Pipeline. He leads the technical development of the ePub standard. Markus Gylling has worked in the field of information accessibility since the late nineties.



Warning : The short papers of this conference have been prepared by BrailleNet who accept any responsibility for them. But presentation materials provided for download (full-papers or slides) have been provided by the authors themselves. They contain more details, more links than the following summary. Please also see the video for the full presentation.

The EPUB 3 specification includes multiple new features that enable publishers to produce and distribute content with much enhanced accessibility and usability. This presentation gave a quick tour of these features from a user perspective, highlighting the most important aspects for the realization of successful and effective inclusive publishing.

As the publishing world starts moving towards EPUB 3, the ebook reading experience can be taken to new entirely levels. Many publishers are already underway adapting their production workflows to enable the production of EPUB 3; suggestions for production workflow approaches to accommodate this revolution in an inclusive manner are given.

What is IDPF and EPUB?

The International Digital Publishing Forum (IDPF) is the global trade and standards organization dedicated to the development and promotion of electronic publishing and content consumption.

The work of the IDPF promotes the development of electronic publishing applications and products that will benefit creators of content, makers of reading systems, and consumers.  The IDPF develops and maintains the EPUB content publication standard that enables the creation and transport of reflowable digital books and other types of content as digital publications that are interoperable between disparate EPUB-compliant reading devices and applications.

With more than 300 members worldwide, the IDPF membership includes book, newspaper, journal and magazine publishers, software and reading system developers, libraries, authors, and other groups interested in digital reading.

The EPUB 3 specification was developed by the IDPF during 2010 and 2011, and reached recommendation status in October 2011.  This latest version of the EPUB specification includes many new features that enable a richer reading experience for everyone (we recommend reading the freely available article What is EPUB 3? from O’Reilly for a comprehensive introduction. The EPUB 3 specification itself is available at http://idpf.org/epub/30).

The DAISY Consortium participated in the development of EPUB 3, and worked to assure that accessibility features were integrated into the specification. The result is that EPUB 3 is actually a superset of DAISY in terms of accessibility support. DAISY is now committed to using EPUB 3 as its main distribution format moving forward, and is also committed to helping build the necessary knowledge and tools to enable mainstream publishers to implement EPUB 3 in an inclusive manner.

The EPUB 3 Specification and accessibility

When we talk about inclusive publishing, we talk about a publishing model where the format(s) made available includes all potential consumers, regardless of ability or disability. EPUB 3 provides a fundament for this model. Below is a quick tour of the cornerstone usability/accessibility features of EPUB 3; we recommend reading the freely available article Accessible EPUB 3 from O’Reilly for more detailed information.

Structure and Semantics: taking control over the markup

The most fundamental principle for inclusive publishing, and a general sound authoring practice, is to assure that the produced content contains necessary structure and semantics. In inclusive publishing, visual styling is not a replacement for proper document markup.  In inclusive publishing, publishers need to take control over the code under the surface and make sure it is retained throughout the publishing process.

EPUB 3 is based on the HTML5 markup vocabulary, and thus includes multiple new structural components that can be used to enhance the content structure. For example, sections, figures, and sidebars can now be unambiguously represented in the markup. For academic publishing in particular, mathematics can now be represented in non-image form (using MathML), and infographics (charts, diagrams) can be represented in non-image form as well (using SVG). EPUB 3 also adds an additional feature called epub:type that can be used to enhance semantics beyond what the base HTML5 vocabulary allows.

The use of proper markup is called a general sound authoring practice because it has positive effects on the reading experience of all users, regardless of ability or disability. Proper structure and semantics is the key to enabling Reading Systems to interact intelligently with users.

Rich Navigation

Rich navigation is another general usability principle that applies to all users. For anything but the simplest leisure literature, absence of good navigation will have immediate negative effects on the reading experience. Did anybody ever read a PDF where the TOC wasn’t working?

EPUB 3 includes the required and dedicated Navigation Document, which offers the following declarative navigation features:

Media Overlays

EPUB3 includes DAISY-style synchronization of text with pre-recorded audio. This feature bridges the gap between the audio book and the text-based ebook – it lets the user decide on which modalities to consume the content in; either text or audio, or both at the same time.

The DAISY text+audio synchronized “Talking Book” is a widely utilized publication form for people with print disabilities. However, this feature also applies to children/adults learning to read, as well as situational disabilities.


Text-to-speech (TTS) interfaces are an increasingly used alternative to pre-recorded audio (albeit with regional variations). This feature is extremely important for academic/professional users, with the core problem being that the more complicated and specialized a text becomes, the more likely is it that default TTS services will fail catastrophically in reproducing the text.

To address this problem, EPUB 3 adds the ability for publishers to include pronunciation and prosody instructions (SSML, PLS, CSS 3 Speech) in the content itself. (This is a complicated technology, and is not something that publishers are expected to master on their own; we are expecting specialized tools to become available to automatically add this information to existing EPUBs.)

Interactivity: ARIA and scripting

One of the main new features in EPUB 3 is the ability to include interactive components in ebooks.  As examples, students can now do interactive tests and quizzes built into the ebook; infographics (charts/diagrams) can be included in gallery-like forms and can be manipulated at will by the user.

On the web, interactive/scripted components have often proved to be an accessibility challenge. EPUB 3 includes rules for how to integrate scripted content into publications, including rules for “progressive enhancement”, which means that the content must retain its informational integrity even when scripting is not available.

EPUB also includes support for W3C ARIA markup to provide state and property information to assistive technologies dynamically. Finally, the IDPF is planning to start a development project to provide open source, reusable interactive component libraries for inclusion in ebooks. Whilst helping cutting development costs for publishers, these libraries will also include state-of-the-art accessibility support.


In retail channels and other provisioning interfaces, it is paramount that print disabled users can be informed which accessibility features are included in a particular ebook.

In parallel to the development of EPUB 3, EDItEUR developed ONIX Codelist 196 to describe accessibility features of e-books. The basic idea is that a) each print-impaired user can characterize their requirements in terms of the various features in List 196, and b) each publisher and retailer can characterize the features provided by a particular product in terms of the features in List 196. The user can then match the two ‘profiles’, thus filtering out items that do not meet the user’s requirements.

Codelist 196 includes informational items such as: navigation via TOC; navigation via Index; logical reading order; alt text; full alternative descriptive text; visualized data also available as text; accessible math; accessible chemistry; print-equivalent page numbering and synchronized pre-recorded audio.

EPUB 3: the new generation of ebooks: principles for inclusive publishing

Don’t think of accessibility as an add-on, think of it as integrated in the general production flow, where increased usability for all users is the ultimate target.

Sound authoring practices are steps taken that increase the quality and usability of the product for all users. Many times, no more production efforts are needed to attain an accessible result. Focusing on retaining structure and semantics in the output is the most fundamental sound authoring practice. On the other hand, using styling and layout to convey meaning, and using bitmap images to carry essential information without providing proper alternative content, are unsound authoring practices as far as inclusive publishing is concerned.

Design interactive ebooks with care. Try to use pre-existing script libraries for interactivity where available, instead of producing our own. Strive to maximize the usability of the result, for all user groups. Use ARIA to aid assistive technologies to convey dynamic information to users.

Media Overlays is also a feature that spans many user groups. Some print disabled users depend on this feature, and some don’t. Some print enabled users love this feature, and some don’t.

As tools for adding TTS enhancements to ebooks arrive, this will be a big step forward for usability in conjunction with screen readers, especially in the academic domain.

Proper accessibility and feature metadata in provisioning interfaces will become paramount to helping consumers make choices.




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