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Re: DRAFT response Re[2]: Request for PFWG WAI review of Omitting alt Attribute for Critical Content

From: Steven Faulkner <faulkner.steve@gmail.com>
Date: Sun, 25 Nov 2007 20:49:16 +0000
Message-ID: <55687cf80711251249w422f97b7hc3f2e1a52fdcb3fe@mail.gmail.com>
To: "Al Gilman" <Alfred.S.Gilman@ieee.org>
Cc: wai-xtech@w3.org

Hi Al,
This draft response does not appear to cover the core issue that
advice from WAI and PFWG was sought:
"the potential accessibility impact of omitting alt attribute for
critical content in HTML 5" [1]

>From the current draft of the HTML 5 spec under the heading "A key
part of the content that doesn't have an obvious textual alternative"

"In such cases, the alt attribute may be omitted, but the alt
attribute should be included, with a useful value, if at all possible.
If an image is a key part of the content, the alt attribute must not
be specified with an empty value." [2]

"When the alt  attribute is missing, the image represents a key part
of the content. Non-visual user agents should apply image analysis
heuristics to help the user make sense of the image." [2]

So in this circumstance

<img src="poot.jpg"> signifies critical content for which no
alternative text has been provided.

But how is this to be differentiated from all the img elements for
which an alt attribute has not been included, but are not "critical

The spec moves the onus from the author to the assistive technology to
provide meaningful alternative text for images under certain
circumstances, which could be quite easily seen as the thin end of the
wedge as any HTML 5 img elements will be valid without alt attributes.
Currently no assistive technology applies image analysis heuristics of
any sophistication (if at all), at best they announce the content of
the title, src or href of the img or its parent. And it is unlikely
that they will be able to for the foreseeable future.

I would really appreciate a clarification on this issue be included as
part of the response.

[1] http://lists.w3.org/Archives/Public/wai-xtech/2007Oct/0044.html
[2] http://www.w3.org/html/wg/html5/#the-img

On 25/11/2007, Al Gilman <Alfred.S.Gilman@ieee.org> wrote:
> <note
> class="inDraft onProcess">
> Earlier discussion on this point can be reviewed at
> http://lists.w3.org/Archives/Public/wai-xtech/2007Oct/thread.html#msg44
> http://lists.w3.org/Archives/Public/wai-xtech/2007Nov/0012.html
> Please comment on this on the XTECH list.
> PFWG could reach consensus on some variant of this
> statement as early as Wednesday, 28 November or
> it could take longer depending on the nature of the
> commentary.
> </note>
> <premises>
> Let's note the following:
> WCAG2 is likely to become a recommendation before
> HTML5, and is reasonably likely to be a Rec for several
> years before HTML5.
> The Web has been under-performing as regards supplying
> good ALT text for images since 1997 when HTML4 was
> published with a syntactic requirement for @alt on all <img>
> elements.
> </premises>
> <position>
> HTMLWG should agree that authors SHOULD provide
> good text alternatives for all <img> elements as
> stated in WCAG2 Guideline 1.1.
> provisional URI:
> http://www.w3.org/WAI/GL/WCAG20/#text-equiv
> </position>
> <position>
> WAI should agree that well-placed informative references
> to existing W3C accessibility Recommendations is a
> suitable way for the HTML5 specification to address this,
> more or less as it has been done in the Specification Guidelines
> Recommendation.
> http://www.w3.org/TR/2005/REC-qaframe-spec-20050817/#address-other-topics
> </position>
> <position
> class="requirement">
> WAI asserts that HTML5 should provide formal semantics
> bound to some markup pattern which enables a readily-followed
> technique for the part of Guidline 1.1 where it says
> <quote
> cite="http://www.w3.org/WAI/GL/WCAG20/#text-equiv-all">
> Decoration, Formatting, Invisible: If it is pure decoration, or used
> only for visual formatting, or if it is not presented to users, then
> it is implemented in a way that it can be ignored by assistive
> technology.
> </quote>
> WAI suggests that the markup pattern
>    @alt=""
> is a 'cowpath' in the language of the HTML5 Principles, in that
> assistive technology is already in the practice of recognizing
> <img> elements with that @alt value as ignorable.
> <note
> class="inDraft">
> Somebody please confirm or deny this.  Do screen readers
> actually skip images with @alt=""?
> </note>
> </position>
> Al
> /self (chair hat off)

with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
Received on Sunday, 25 November 2007 20:49:30 UTC

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