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Publishing issues for Silver
This document provides a general description of issues both current and future that impact on digital publishing accessibility and that may be useful to consider in the design and requirements for the W3C Silver accessibility guidelines.
The inclusion of accessibility metadata in web publications is an important device in helping discover their usability, and WCAG 2.1 will introduce such metadata as an optional reporting feature. Schema.org includes accessibility metadata for use describing Web resources, which is based on IMS Global's Access for All metadata. Although metadata may not technically make the content itself accessible, users benefit from being able to quickly determine whether content will be suitable for them without having to first consume the content.
One obstacle faced during the WCAG 2.1 revision was lack of support for discovery via the metadata. By the time of Silver, this metadata is expected to be in use and supported by vendors in the EPUB 3 ecosystem and, depending on timelines, also in Web Publications and EPUB 4. Efforts are also continuing to get Web search providers to expose this metadata.
The current accessibility guidelines use the URL as the unit of conformance. This approach is problematic both for web publications and EPUB, as content is typically spread across multiple pages, each with its own URL (i.e., they are not always packaged). Web Publications and EPUB 4 may define a single URL for the publication manifest, but publication itself will still consist of many independent resources (pages). The entire publication needs to conform, but the current definition is not clear how this will work.
The expectation of HTTP is also problematic as packaged publications are often not situated on a web server. Packaging is intended to allow publications to exist on the file system (file protocol) and be transferred between users in other ways (e.g., FTP).
The needs of web publications and epub dovetail in that both are sets of web content. The word "publication" is a much more generic term that is applied to the generation of all kinds of other physical and digital documents: PDF, Word files, ODF, and even HTML itself. The needs of all these formats are not the same, although there will be many similarities.
If Silver takes a modularized approach to accessibility, we will only be able to focus on web pub/epub. We cannot attempt to define a module of criteria for all publication formats. Similar to PDF, our goal may only be to define techniques for achieving general WCAG conformance.
How to handle third-party content that is not controlled by the author is another open problem. While the current accessibility guidelines allows regions to be excluded from conformance reporting, third-party content is often critical to the reading and understanding of a publication (e.g., open textbooks). The author is not always going to be aware when such included content is changed or what impact it will have.
In some cases, this will be a non-issue (e.g., advertisements). In others, it should not be possible to simply exclude the third-party content from consideration (e.g., applications and widgets needed to understand the content).
It also may not be possible to take third-party content offline or to include it in a packaged version. If such content is packaged, does the author assume responsibility for ensuring it conforms?
With SMIL support on the Web never being fully realized, and now disappearing, a means of providing synchronous audio and text playback is necessary (i.e., the ability to have prerecorded audio played back at the same time as text is highlighted). There are more than just the technical challenges of expressing the synchronization points, though. Navigation and features such as navigation skippability and escapability need to be defined to improve this kind of reading experience, and best practices need to be codified.
It is expected that web publications will be available for both online and offline reading, but not all content will function correctly, or at all, when offline. The accessibility of the publication may depend on the reading state, in other words, although this may be true for all readers. Authoring techniques that avoid core content becoming inaccessible may be needed, as will user awareness that just because a publication can be taken offline doesn't mean it has been designed to be.
For example, a publication might include quizzes that can only be evaluated when a student is online. If the student is not aware of this, they may lose time answering the quiz without being able to verify their results. If the quiz cannot be stored and submitted later, the work they do will be lost.