Using Adobe InDesign to create accessible EPUB 3 files

Original Author(s): Prashant Ranjan Verma

Adobe InDesign CC and InDesign CS6 can be used to create eBooks with features that make them accessible to people with different disabilities.

Publishers must follow best practices for content markup and make use of accessibility guidelines when they export their content from InDesign in EPUB 3 format in order to provide accessibility to all readers.

To learn more about EPUB 3 format and the built-in accessibility features, refer to the following free O'Reilly publications:

Content preparation

Before you get started with preparing the content in InDesign refer to these helpful guidelines:

It is highly recommended for all to review the above mentioned guidelines. In summary, the following steps need to be completed:

Separate content and presentation

Visual reading is only one way of accessing content. Do not use visual-only cues such as coloured text, font size or positioning as the only clue to the meaning or importance of a word or section. Do not use tables or pictures of text to control the appearance of the content. The meaning of the content should be the same both with and without any styles or formatting applied.

Structure the content

Mark up each section in the document using appropriate styles (e.g. h1, h2..). Provide a correct hierarchy of sections and include page numbers.

Use images only for pictures, not for tables or text

Any content embedded in an image is not available to visually impaired readers. Use proper and complete markup for text and tabular data.

Use image descriptions and alt text

Every image should have a description, caption or alt text unless it is solely decorative.

Use MathML

MathML makes mathematical equations accessible to everyone by eliminating the ambiguity of a verbal / audio description of a picture. There are many tools available to support MathML creation.

Provide alternative access to media content

Make sure the native controls for video and audio content are enabled by default. Provide fallback options such as captions or descriptions for video and transcripts for audio.

The bottom line

  • Adhere to standards
  • Follow best coding practices
  • Take care of non-textual content (images, video and audio)

The resulting output will be compatible with standard assistive technologies and accessible to people with visual, sensory and intellectual impairments.

InDesign tips

The above guidelines need to be implemented using the tools available for InDesign. The Adobe InDesign Accessibility page has tutorials and videos to help you prepare the content in accordance with accessibility guidelines. Note that the tips for creating accessible PDF files are applicable for creating EPUB 3 files as well.

  • Use the Mapping styles and tags features for semantic markup of the content. Assistive technologies such as screen readers rely on the styles used in the content to convey important information such as the presence of headings to the users.
  • Use the Articles panel to organize your content by dragging images, text frames, and other content. Use this tool to control the sequence of text, images, and graphics in the exported document, ensuring it is optimized for accessibility.
  • Articles panel in InDesign CC
  • Add Alternative Text for Images so that non-visual users can understand the graphical content by reading the descriptions of images with assistive technology.
  • Take care of metadata. Appropriate metadata is good for accessibility and search engine optimization.
  • Export to EPUB 3
  • Validate your EPUB 3 file: You can use the online EPUB 3 Validator maintained by IDPF to make sure that your EPUB 3 file does not have any errors. This site uses EpubCheck to provide validation information for documents in EPUB 2 and EPUB 3 formats. If you are creating commercial EPUBs in volume, you must install EpubCheck instead of using this site.

See also

DAISYpedia Categories: 


This page was last edited by PVerma on Wednesday, September 14, 2016 03:14
Text is available under the terms of the DAISY Consortium Intellectual Property Policy, Licensing, and Working Group Process.

Comments

My questions are not specific to Adobe InDesign, but to fixed-layout EPUB.

To what extent should one expect accessible results in fixed-layout EPUB in the following circumstances:

1. A sentence breaks across pages. Will AT see it as a single sentence?
2. A word breaks across pages using a soft-hyphen. Will AT see it as a single word?
3. A table spans two pages. Is it presented to AT as a single table?
4. A MathML equation spans two pages. Is it presented to AT as a single equation?
5. A page includes both body and sidebar content, both of which continue on a following page. Are the respective sections of content on each page associated with each other?

Thanks,

Duff.

Thank you for posting your questions to DAISYpedia.

We include articles on various publishing related topics as our community finds them useful. At the same time, we recommend reflowable (renditions of) EPUB 3 as typically this way digital publication is more accessible than pre-paginated (fixed layout) EPUB 3. Also, for example, reflowable content most likely will include tables that adapt to screen size, and are accessible to readers who may rely on read-aloud functionality. Increased accessibility is also achieved through semantic structuring.

Fixed-Layout Publications MUST meet all of the following criteria in order to be accessible:

  • be constructed from text-based XHTML or SVG Content Documents (i.e., text content is not represented as images)
  • use appropriate [HTML5] markup for the structures being represented (i.e., avoid the generic SPAN and DIV elements unless no more appropriate markup is available
  • retain the logical reading order of the text content (i.e., text appears in the markup in the order in which it is expected to be read);not position text over background images in such a way that it will present difficulty reading (e.g., poor contrast).

Varju

Thanks for responding. However, I’m not sure I understand how your response addresses my specific questions, for example, pertaining to words, sentences or tables that break across fixed-layout pages.

Or perhaps (based on your answer) I should be asking... "What are the "appropriate" HTML5 markup for structures that span two (or more) pages in a fixed-layout EPUB?"

Well, it is a bit challenging to respond to your first set of questions as there are several variables that have to be considered: device or platform, digital content and AT :)

Fixed-layout files are often created for a predetermined platform (iPad or Kindle Fire for example) and customized to its reading-system specifications, so that consumers of the content will see exactly what the designer envisioned.

Fixed layout is also an accommodation for publishers who want pixel-precise pages. Each page is a self-contained html document, so if you have objects that spill across pages, whether sidebars, images or paragraphs, there is going to be a logical break at the Assistive Technology level as it transitions from reading one document to the next.

Creating a fixed layout that meets your specific reading needs may require you to get deep into the HTML and CSS.

Pariah S. Burke has written a great book “Creating Fixed-Layout eBooks” where he describes specific details and provides code samples: https://itun.es/us/zNewK

Suggested reading:

BISG's Field Guide to Fixed Layout for eBooks

EPUB 3 EDUPUB Profile