Guidance and Standards
As a rule, developers should follow the top tips outlined below in order to ensure that EPUB files are as accessible as possible for everyone. Accessibility is not, however, an on/off switch and what is accessible for one person may not be for another – we all have different access requirements and you should try to incorporate as many features as possible to assist with that access. Every contribution and refinement of your files counts and it’s important that you start somewhere.
Your client / publisher may have instructed you on their accessibility requirements and you should, most certainly, follow these instructions but it is good to be aware of all possibilities for increased access to content and to include these also, with your client’s agreement.
If your client hasn’t asked specifically for any accessibility features to be included within their EPUB file then we encourage you to educate and explain that this is the method that you prefer to work to and that your files are delivered with as many accessibility features included as possible. You can direct them to the publisher’s section of this website to give them greater insight.
These are some of the main areas that you should concentrate on when producing your EPUB files. Include these features from the ground up and try to avoid retro-fitting your files as this will be more time consuming and costly. For greater detail and information on standards see the list of resources at the end of this page.
The EPUB specification is maintained and managed by the Publishing@W3C Group. Information concerning the various working groups, how you can participate, the standards and profiles is available at the Publishing@W3C site together with information on the various technical specifications of the EPUB formats and its profiles.
EPUB 3 is built on open web standards, and the accessibility principles outlined in the Web Content Accessibility Guidelines (WCAG) apply. They specify that digital content should be:
- Text alternatives are provided for non-text content
- Captions and other alternatives for multimedia are available
- Content can be accessed in different ways, also using assistive technologies, without losing meaning
- Users can see, read and hear content
- All functionality is available from a keyboard
- Users have enough time to consume content [Pause and Stop are provided if needed]
- Content does not cause seizures
- Users can navigate and find content
- Text is readable and easily understood
- Content is displayed and is operable in predictable ways
- Users can avoid and correct mistakes
- Compatible with current and future user tools
For detailed information, please read the W3C Guide Understanding WCAG 2.0.
WAI-ARIA is a technical specification defining a common host language semantic accessibility API and framework. This framework allows web browsers to map the accessibility semantics in web content to platform-specific accessibility APIs. Therefore, web content can be interoperable with assistive technologies. The goals of this specification include:
- Expanding WAI-ARIA to produce structural semantic extensions for the digital publishing industry
- Aligning with a new governance model for modularization and extensions to WAI-ARIA
- Providing structural semantics extensions supporting assistive technologies
- Enabling semantic navigation, styling and interactive features used by readers
Read more about the roles defined in this specification: EPUB Structural Semantics Vocabulary.
To get a detailed explanation, please review the WAI-ARIA Introduction. Find out how it applies to Rich Internet Application Accessibility.
This recently published specification assists with meeting requirements for EPUB content and are a good starting point for well structured accessible content files. The specification is structured so that there is a set of universal high-level requirements, while a separate techniques document identifies specific practices and how they are implemented in the different flavours of EPUB.
There are many areas of technical work at W3C in which the publishing community is already participating. Among these are the Digital Publishing Interest Group, the CSS Working Group, and Accessible Rich Internet Applications Working Group. Participation in Interest and Working Groups is open to regular members of W3C.
We recommend the following guidelines for developers:
Designed to give publishers a quick and up to date reference tool, The Quick Start Guide is written in clear, non-technical language and is available in English, French, German, Italian, Korean and Spanish for free in EPUB 3 from the BISG website.
Accessible EPUB 3 – Matt Garrish
Published by O’Reilly Media and available for free download this book provides a definitive guide to accessibility and EPUB 3