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RE: HTML5: Techniques for providing useful text alternatives

From: Jonathan Avila <jon.avila@ssbbartgroup.com>
Date: Mon, 17 May 2010 08:27:19 -0400
Message-ID: <340b59e98992bc954e6d21b2acd22e22@mail.gmail.com>
To: w3c-wai-ig@w3.org
Steven, this document will be very useful to developers.  One user group
that I feel should be added under "Examples of scenarios where users
benefit from text alternatives for images" are users with visual
impairments who do not use screen readers or assistive technology.  This
includes users with color deficiencies and users with low vision.

This is important because many users with low vision may be able to read
the text and interpret most images but may need alternative text for
certain images.  When alt text is only displayed with the alt attribute,
users of some browsers and keyboard only users in this category will not
have access to this text.

In addition, related to example 4.1, using the alt attribute alone would
IMHO not be sufficient for WCAG 2 compliance because the alternative for
those who cannot distinguish colors is provided through the alt attribute.
If a person with color deficiencies with normal acuity were viewing this
image with a browser such as Firefox they would not have access to the
alternative text.

My recommendation in this latter example is to require that any meaning
conveyed in the image via color is in additionally displayed without the
use of color directly in the image (hatching, lines, etc.) or as text
visible on-screen.  The alt attribute does not suffice in these
situations.  I think this note would be a great addition to the document
that you are authoring.

Jonathan


-----Original Message-----
From: w3c-wai-ig-request@w3.org [mailto:w3c-wai-ig-request@w3.org] On
Behalf Of Steven Faulkner
Sent: Monday, May 17, 2010 6:51 AM
To: W3C WAI-XTECH; WAI Interest Group
Cc: HTMLWG WG; WebAIM Discussion List; wsg@webstandardsgroup.org
Subject: HTML5: Techniques for providing useful text alternatives

HTML5: Techniques for providing useful text alternatives
http://dev.w3.org/html5/alt-techniques/

This document is a work in progress currently edited by me, I
encourage anyone with an interest to contribute to its development.

Document aims:
* Provide clear and practical advice on how to  provide appropriate
text alternatives for images using currently supported  techniques
* How to make use of the new features available in HTML5 and WAI-ARIA
for providing text alternatives.
* Understanding the advantages and disadvantages of each technique in
reference to browser and assistive technology support.
* Provide normative rules for each technique in regards to whether its
correct use results in a conforming HTML5 document.
* Harmonization of HTML5 document conformance in regards to image text
alternatives with WCAG 2.0.

The document has been put forward as a First Public Working Draft in
the W3C HTML WG, it is expected this initial publication will occur
next month.

How you can help:

If you are not a member of the W3C HTML WG:
Email the HTML WG public comments list: public-html-comments@w3.org
Email me: faulkner.steve@gmail.com

Or preferably

File a bug

If you are a member of the HTML WG email the list or me  or preferably
file a bug
http://www.w3.org/Bugs/Public/enter_bug.cgi?product=HTML%20WG&component=al
t%20techniques%20(editor:%20Steven%20Faulkner)

-- 
with regards

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

www.paciellogroup.com | www.wat-c.org
Web Accessibility Toolbar -
http://www.paciellogroup.com/resources/wat-ie-about.html
Received on Monday, 17 May 2010 14:20:31 GMT

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