At this time, only 5% of ebooks are built with accessibility in mind. What can authors, editors, ebook developers, and publishers do so a broader audience can access their ebooks? You can start by following the 10 accessibility tips below. It is important to include as many of these features as possible to improve the accessibility of your content. Check out the Accessible Knowledge Publishing Base for an in-depth look at how to implement these tips and more.
- Does your ebook include Image Descriptions?
It is critical to add meaningful alternative text to images (figures, maps, photographs, illustrations, cover images, logos, etc.) that are not purely decorative or not fully described in-text. Remember that it is not only a blind person who may struggle to understand what an image or graph is trying to convey! Image descriptions should generally be no more than 200 characters; if a longer description is required, link out to a non-linear HTML file with a long description. Any images that are purely decorative – such as curlicues at the start or end of chapters – should have empty alt text (
role=“presentation”in the markup. This markup tells the assistive technology that there is nothing to see, so it will skip over the image. Image descriptions are best created by the person - often the author or editor - who has the best grasp of what they are trying to convey through the image.
- Does your ebook properly identify all Headings?
The ability to navigate throughout the text is essential for accessibility purposes and the more opportunities for navigation that you can offer, the more accessible your product will be. Headings are one of the primary means of navigation for readers who use assistive technology. Assistive technology will announce the heading levels to readers to help them make sense of the content. The hierarchy of your ebook should follow the hierarchy of the table of contents. If heading tags aren’t used to identify major sections and subsections then your ebook will be like a long run-on sentence to people using assistive technology. Always use headings in order: a document with three levels of headings should use Heading 1, Heading 2, and then Heading 3, not Heading 1, Heading 3, and Heading 4, or any other combination.
- Does your ebook use HTML5 tags?
EPUB 3 uses HTML5, which supports more semantically meaningful markup. This means computers can understand the structure of your content and communicate that information to readers who will then be able to follow your ebook from beginning to end without being interrupted or becoming lost. Primary material in your ebook should be inside a
<section>tag, while secondary content, such notes, sidebars, and marginalia, should be inside
<aside>tags. Images and captions should be marked with
- Does your ebook have a Pagelist?
The Pagelist is one of the hallmarks of EPUB 3 - it's a list of all the pages in the ebook, and they correspond to the page numbers in the print edition. If your ebook complements a print book, then include a print corollary pagelist. Also, be sure to embed a dc:source ISBN in the OPF file (
<dc:source>978-1-000-0000-0 </dc:source>) to let readers know which print book it's based on. Students and book club members will especially appreciate this navigational aid, which gives them the ability to keep in sync with readers of physical books!
- Does your ebook have Landmarks?
Just like a Pagelist, Landmarks is another key feature of EPUB 3. Landmarks provide another way to navigate the content by marking major sections of your ebook with semantic tags that make it machine-readable. A full set of landmarks – frontmatter, bodymatter, backmatter, toc, list of illustrations/figures/maps, pagelist, copyright page, contributors, endnotes, index, glossary – will make your ebooks easier to use for a variety of readers.
- Does your ebook use ARIA?
HTML5 (used in EPUB 3) allows you to incorporate ARIA - a web standard that is used by assistive technology to facilitate navigation for the reader. Assistive technology users can navigate to sections of an ebook using ARIA landmarks. Consider using it to add an extra layer of navigation and semantics to your content.
- Does your ebook identify the main Language and any Language shifts?
Be careful to mark language shifts. By doing so, you ensure that content is accurately read aloud by assistive technology; there is nothing worse than an English-speaking robot reading French or Spanish as though it’s English! The main language of the ebook should be declared in the OPF, and also on the root HTML element at the top of each HTML file.
- Does your ebook properly identify Context Breaks?
The semantically correct way of marking editorial spaces or context breaks is with a
<hr/>tag. Without the
<hr/>tag, assistive technology will read right through that context break without pause, and, as you might imagine, this will cause confusion! You can assign a class and some styling behaviour to that tag, i.e. if you want to call a dingbat or other image.
- Does your ebook identify the Page Title at the top of each file?
A frequently misunderstood piece of the ebook puzzle is how to treat the title at the top of each HTML file. It should not contain the name of the book, rather it should be descriptive of the content that the single file contains, i.e. “Chapter Seven - High Places”. Meaningful page titles allow users to find and navigate documents without having to read them first.
- Does your ebook include Accessibility Metadata?
Accessibility metadata is how you document the accessibility of a publication. There is a full set of both ONIX and schema.org metadata that you can copy and paste into all your ebook. This metadata will multiply your content’s accessibility simply by making it more discoverable. ONIX allows metadata about which specific features that promote accessibility have been included in a particular book, i.e. table of contents, alternative text descriptions, print-equivalent page numbering, etc. The publisher and retailer can use ONIX to allow print-impaired readers, librarians, and other potential purchasers to discover suitable books.