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Re: Suggested addition to 1.1

From: Anne Pemberton <apembert@erols.com>
Date: Mon, 12 Feb 2001 17:11:48 -0500
Message-Id: <>
To: Charles McCathieNevile <charles@w3.org>, Marti <marti@agassa.com>
Cc: <w3c-wai-gl@w3.org>
Thanks, Charlie,

	I thought it made more sense to put the text equivalent on the page not on
the picture itself, since there is no reason for someone who cannot see it
anyway to have to download it to get the alt text. 

	I looked over the information you sent on embedding information in a
graphic, but the sites were long on words and short on examples. The one
example I found let me view the picture, but I had to download the
explanatory data and when I tried, I didn't have the plug in needed to use
it. Sigh! I will be good when it's ready, but it's not for prime time yet!


At 09:12 PM 2/11/01 -0500, Charles McCathieNevile wrote:
>Some thoughts:
>Providing the small image as a link to a larger one (when the image is used
>as an image, not a link to something else), is a good thing to do. Where the
>link to the larger version of the image appears, there should also be textual
>equivalent information. Some of this might be "inline" such as the HTML alt
>attribute, and some of it might be via a link, such as the HTML longdesc
>This is how to meet the requirement that someone reading a page can find out
>what is on the page.
>For an image itself, there are actually techniques for including alternative
>information directly in the image.
>There is a W3C Note (Describing and retrieving photos using RDF and HTTP) and
>an associated set of free software that explains how to include all kinds of
>information, including a title, authoring information, a description, links
>to recorded-audio description, and so on in a jpg file, and how to get it out
>again. The same principles can easily be applied to PNG and GIF formats, but
>the tools developed do not currently handle those formats. The Note is at
>For SVG images, there are a range of techniques that can be used, and another
>W3C Note (Accessibility features of SVG) that describes how to use them. That
>Note is at http://www.w3.org/TR/SVG-access (and is in the intial stages of
>being revised and updated)
>And for multimedia stuff like movies there is a whole raft of work available.
>The Authoring Tool Accessibility Guidelines has requirements that tools use
>this kind of information to help authors by proposing equivalents, and that
>they acutally help authors to produce images that include it. If people asked
>about ATAG conformance when they are looking for image-processing software as
>well as looking for software that could take advantage of this in authoring
>Web pages, it would encourage the companies who are already making efforts in
>that direction.
>Charles McCN
>On Sat, 10 Feb 2001, Marti wrote:
>  >
>  > How does this simple and elegant solution to minimizing image
downloads to
>  > users  pose a problem for disabled human users? Seems to solve the
>  > of low vision users who want to see the picture at their use level, make
>  > the picture available to be printed easily, and allows the use of
>  > photos to illustrate the page.
>  Anne,
>   I am not sure I understand what you are asking about here? If you mean the
>  link directly to an image file that I said could be a violation, I think
>  answered the question yourself, there is no way to attach alt or longdesc
>  information if you do that. On the other hand, you can wrap some very
>  html arond it and allow the alt information.
>  In a way, linking directly to an image file is like linking to a PDF
>  document which has been created as just an image.
>  Marti
>Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409
134 136
>W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617
258 5999
>Location: I-cubed, 110 Victoria Street, Carlton VIC 3053, Australia
>(or W3C INRIA, Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex,
Anne Pemberton

Received on Monday, 12 February 2001 17:09:29 UTC

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