From HTML WG Wiki
Re-open Request for ISSUE-31: Author conformance requirements for the alt attribute on images
This Re-open request and Change Proposal addresses the issue of Working Group (WG) location of guidance on alternative text. Currently there are two divergent versions of similar material among the set of HTML5 deliverables. While the previous decision by the HTML WG resulted in an additional document providing guidance on alternative text, the guidance on alternative text remaining in the main HTML WG specification continues to contain duplicative, in some cases inaccurate in other cases inadequate material despite multiple bugs having been filed to remove/modify or add that guidance 9216, 9215, 8827, 8652, 8645, 7262.
This proposal provides a rationale for re-opening the question of WG location of alt guidance, and change proposals for resolving current problems in guidance for alternative text in the main HTML5 specification and for moving primary conformance requirements on alternative text to the Web Content Accessibility Guidelines Working Group (WCAG WG).
The grounds for re-opening are:
- a pattern of rejected bugs relating to the content of the text alternative advice in HTML5
- The issue is still unresolved as evidenced by 2 sets of contradictory normative requirements, each of which duplicate in some part the superset of normative requirements and informative guidance contained within WCAG 2.0 and the Techniques for WCAG 2.0, while a subset of the normative requirements contained in the HTML5 specification contradict WCAG 2.0 documents.
- The majority of normative authoring requirements for alternative text currently contained within the HTML5 specification are not HTML5-specific, but are also useful and relevant for authoring content in other specifications besides HTML5. They should therefore not be prescribed within HTML5.
- Much of the normative requirements for alternative text currently in "HTML5: Techniques for providing useful text alternatives" are relevant for authoring content in other specifications. Accuracy, appropriateness, and effectiveness for meeting user needs across diverse contexts for alternative text are all important to ensuring equivalent access to information that is visually presented. The WCAG WG is more suited to development and vetting of the requirements and guidance of alternative text at this level, while the product of that development and vetting process can be equally available to developers using any specification.
The HTML 5 specification suite currently has two sets of advice about providing useful text alternatives. One is 18.104.22.168 Requirements for providing text to act as an alternative for images, the other is a separate closely related document HTML5: Techniques for providing useful text alternatives.
A subjective summary of the genesis of these resources is that the HTML 5 draft long ago made the
alt attribute an optional feature of the
img element, because use cases could be presented for which a good value was unknown. Accessibility advocates objected that this renders the
img element incomplete from a non-visual browsing perspective and deprioritizes accessibility in the HTML 5 conformance model. To partially address that concern while retaining a deterministic conformance model, content was introduced into the specification that detailed circumstances in which the
alt attribute is required or particular values are valid; this is the section embedded in the specification referenced above. Accessibility advocates, including users with visual disabilities who rely on alternative text for access to visually presented content, however, noted that this did not adequately address the initial concern and did not present advice that uniformly and completely represents accessibility best practices. They attempted to improve this section through a detailed Change Proposal, but ultimately the difficulty in gaining traction on that in the specification led to the spinning off of the change proposal as a separate deliverable of the HTML Working Group, which is the second resource referenced above.
While a lot of good work has been done, the current state is that there are two obviously divergent versions of the same material among the set of HTML deliverables. While in general the HTML 5 specification focuses on defining the features of the HTML 5 language without overly prescribing authoring or user agent expectations, the section on text alternatives is a notable exception. The confusion it introduces on what constitutes a normative part of the HTML 5 conformance model is a part of the problem that has led to difficulty agreeing on the appropriate content of that section. Separating it would allow a clean conformance model for HTML 5. Note that separating this content does not relieve HTML 5 of the responsibility to provide the features necessary to author accessible content, it merely deconfounds the HTML 5 conformance model from the accessibility practices.
The majority of normative authoring requirements for alternative text currently contained within the HTML5 specification are not HTML5-specific; such advice is equally relevant to other document formats such as PDF, SVG, Microsoft Word, ODF and others. They should therefore not be prescribed within HTML5. Additionally, the majority of the normative requirements for alternative text currently in "HTML5: Techniques for providing useful text alternatives" are useful and relevant for authoring content in other specifications besides HTML5, and therefore should not be explicitly associated with HTML5, but rather be seamlessly available to authors of HTML5 and to other specifications through links and/or a common interface as needed.
Much of the normative requirements for alternative text currently in "HTML5: Techniques for providing useful text alternatives" are relevant for authoring content in other specifications. Accuracy, appropriateness, and effectiveness for meeting user needs across diverse contexts for alternative text all are important to ensuring equivalent access for people with visual disabilities to information that is visually presented. These requirements need to be carefully developed and and vetted among accessibility experts, including users with disabilities. Requirements and guidance needs to be assigned to normative or informative levels, according to extensive experience regarding which guidance is more fundamental and/or more well-tested, and which is more advisory or even experimental. Furthermore, as guidance on alternative text continues to evolve, it requires ongoing vetting and maintenance by a Working Group charged with this scope of work, and chartered to produce periodic updates of accessibility guidance that is relevant across different technical specifications including HTML5. The WCAG WG is more suited to development, vetting, and ongoing maintenance of guidance of alternative text; and the products of that ongoing development, vetting, and maintenance can be equally available to developers using any specification.
For example take the following from the HTML5 specification.
22.214.171.124.3 A phrase or paragraph with an alternative graphical representation: charts, diagrams, graphs, maps, illustrations Sometimes something can be more clearly stated in graphical form, for example as a flowchart, a diagram, a graph, or a simple map showing directions. In such cases, an image can be given using the img element, but the lesser textual version must still be given, so that users who are unable to view the image (e.g. because they have a very slow connection, or because they are using a text-only browser, or because they are listening to the page being read out by a hands-free automobile voice Web browser, or simply because they are blind) are still able to understand the message being conveyed. The text must be given in the alt attribute, and must convey the same message as the image specified in the src attribute. It is important to realize that the alternative text is a replacement for the image, not a description of the image.
The only HTML specific aspects of the above are (bolded) references to the img element and its alt/src attributes. The rest of what is specified relates equally to many document formats available from the web. It is the mechanics of providing text alternatives that is an integral part of HTML and rightly prescribed in the HTML5 specification. The requirements for what an author is to provide as a text alternative for a graphical object is not unique to HTML and therefore the argument for its inclusion in the HTML specification is considerably weaker and the argument for it to be normatively specified in HTML5 is especially weak.
The HTML WG decision on issue 31 stated:
"This issue can be reopened if new information come up. Examples of possible relevant new information include: *Identification of a systemic pattern of problems based on specific bug reports and their ultimate resolution and identify a solution that specifically addresses the underlying causes. * Publication of a new version of WCAG that contains sufficient concrete examples relevant to HTML5 which would serve as a suitable reference."
The following bugs indicate such a pattern:
- request for addition of webcam example - rejected
- request for an addition of a Captcha example - rejected
- request to limit the length of conforming text alternatives for figcaption - rejected
- request to change the conformance requirements for decorative images - rejected
- request to not allow the title attribute antipattern to be used for images - rejected
This change proposal resolves all of these issues as all of the issues are resolved in HTML5: techniques for providing useful text alternatives:
- conformance requirements and Webcam advice provided
- conformance requirements and Captcha advice provided
- advice on alternative text length provided
- conformance requirements and advice on images that may be considered decorative
- conformance requirements on title attribute usageand advice on how to markup captions for images
We emphasize that WCAG 2.0 is not a static specification nor a single document by design. Rather, the Web Content Accessibility Guidelines expressly specifies, Understanding WCAG 2.0, reiterates that these two documents are to be taken together along with the continually evolving Techniques for WCAG 2 as constituting "WCAG 2.0." An update to any of them constitutes and "update to WCAG" By design WCAG is a "living specification" because we accomodate technological development by continually adding and adjusting WCAG techniques
Thus, relocating the HTML5 techniques document to the WCAG working group fulfills the second revisiting issue prerequisite: "Publication of a new version of WCAG that contains sufficient concrete examples relevant to HTML5 which would serve as a suitable reference." As all WCAG techniques constitute an update to WCAG 2.0. Furthermore, relocating this document to WCAG will ensure its ongoing maintenance in the ongoing work of the Joint PF and WCAG Task Force on HTML 5 Techniques.
Remove the following non- HTML specific normative requirements from HTML5 specification as they are are equally applicable to any document format published on the web that can include non text objects:
- 126.96.36.199.1 General guidelines
- 188.8.131.52.2 A link or button containing nothing but the image
- 184.108.40.206.3 A phrase or paragraph with an alternative graphical representation: charts, diagrams, graphs, maps, illustrations
- 220.127.116.11.4 A short phrase or label with an alternative graphical representation: icons, logos
- 18.104.22.168.5 Text that has been rendered to a graphic for typographical effect
- 22.214.171.124.6 A graphical representation of some of the surrounding text
- 126.96.36.199.7 A purely decorative image that doesn't add any information
- 188.8.131.52.8 A group of images that form a single larger picture with no links
- 184.108.40.206.9 A group of images that form a single larger picture with links
- 220.127.116.11.10 A key part of the content
- 18.104.22.168.11 An image not intended for the user
- Link to the WCAG 2.0 normative requirements for non text objects: [http://www.w3.org/TR/WCAG/#text-equiv Guideline 1.1 Text Alternatives: Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
- Link toHTML5 techniques for providing useful text alternatives
- Link to the general WCAG 2.0 text alternative techniques in order to provide seamless access to comprehensive and technology-neutral guidance on provision of alternative text that meets the requirements of people with visual and other disabilities.
- Make HTML5 techniques for providing useful text alternatives a WAI/HTML WG deliverable.
- Remove normative aspects of the techniques document.
- Remove duplicative and/or inadequate requirements; - Allow development, vetting, and maintenance of guidance on alternative text under an appropriately scoped Working Group already chartered for this scope and for ongoing maintenance of accessibility guidance; - Provide guidance on alternative text that is technology-neutral in a location that can be made equally available to all relevant specifications.