Tips for Creating Accessible EPUB 3 Files and web content for the GDL

Tips for Creating Accessible EPUB 3 Files and web content for the GDL

1. All text must be available in a logical reading order

The text must not be presented as images, be reordered by CSS, or require scripting to be accessed. Use structural markup to define the natural reading order of the primary narrative and to distinguish secondary material such as footnotes, references, figures, and other auxiliary content.

2. Use images only for pictures, not for tables or text

Any content embedded in an image is not available to visually impaired readers. If the textual contents of a table or image are required for comprehension of the document, use proper and complete markup for text and tabular data, including headers and scope attributes for tables. If images of text are unavoidable, provide a description and transcription of the text and use accessible SVG. Accessible SVG graphics allow text in images to be rendered in an accessible way. They can also make it possible to deliver tactile images electronically to blind users with appropriate devices or to help automate the creation of tactile images that can be mailed to the reader with minimum human intervention.

3. Use image descriptions and alt text

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

4. Separate presentation and content

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.

5. Use MathML

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

6. 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.

7. Make interactive content accessible

Interactive content using JavaScript or SVG should be accessible. All custom controls should fully implement ARIA roles, states, and properties, as appropriate.

8. Use accessibility metadata and include the metadata in the EPUB file 

As part of a general good practice of documenting the accessibility of your content, provide accessibility metadata in your files so end users know what features are there and search engines can discover your accessible materials.

The specification for GDL metadata is found here.

9. Include page number

Page numbers are the way many people navigate within a book. For any book with a print equivalent, use the epub:type=”pagebreak” attribute to designate page numbers. Include the ISBN of the source of the page numbers in the package metadata for the book. A tag for a page number might look like <span xml:id=”page361″ epub:type=”pagebreak”>361</span>.

10. Define language(s) for the content 

To make sure each word will be rendered correctly, specify the default language of the content in the root html tag. Indicate any words, phrases or passages in a different language by using the xml:lang attribute: <span xml:lang=”fr” lang=”fr”>rue Saint-Andre-des-Arts</span>.  Mark the language with a BCP47 compliant language tag (RFC5646).

This work is a derivative of “Top Tips for Creating Accessible EPUB 3 Files” by Benetech, used under Creative Commons Attribution-NonCommercial 2.5 Generic License. This work is licensed under CC BY 4.0, by The Global Digital Library

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