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RE: DRAFT response Re[3]: Request for PFWG WAI review of Omitting alt Attribute for Critical Content

From: Emmanuelle Gutiérrez y Restrepo <coordina@sidar.org>
Date: Thu, 29 Nov 2007 14:09:57 +0100
To: <wai-xtech@w3.org>
Message-ID: <007701c83289$3208b940$0a00a8c0@EMMYSIDAR>

	
I am sorry to disagree with Charles, but I think the nule alt (alt="") must
be used only when the image does not convey any information.

Today, increasingly, there are tools that extract images, videos and other
multimedia objects on the Web, so it is important that each of these
elements leading associated its alternative text, although in principle be
presented in a page which would explain its contents. 

Moreover, we must think that users of alternative text are not only those
who did not see and receive information on the structuring of the content
via a screen reader. The alternative text is also important for those who
can see and surf without downloading the images. For them it is possible
that the relation of the image (not presented) with the text that describes
is not so clearly associated due to the layout of the elements on the page.

IMO the Charles's example can be better if we use the alt ant title in
another way:

<html xmlns="http://www.w3.org/1999/html">
<head>
   <title>Flickr Photo from Chaals</title> </head><body>
   <h1>Me and my cat playing</h1>
   <p><img alt="Charles with his cat" title="photo of Charles McCathieNevile
playing in the park with his cat ***" src="FYDJ.jpg"/></p>
   <p>tags:</p>
   <ul>
    <li>chaals</li>
    <li>fanstasy</li>
    <li>mog</li>
   </ul>
  </body>
<html>

I'm sure that my example can be improve, but the importan think is that we
can use H1, p, alt and title in a useful way, and for this we need only to
know our own language (And the English is not mine <green>) 

Best regards,
Emmanuelle
Emmanuelle Gutiérrez y Restrepo  	Fundación Sidar
Coordinadora del SIDAR			www.sidar.org
Email: coordina@sidar.org
Tel.: +34 - 91 725 71 47		


-----Mensaje original-----
De: wai-xtech-request@w3.org [mailto:wai-xtech-request@w3.org] En nombre de
Charles McCathieNevile
Enviado el: jueves, 29 de noviembre de 2007 12:58
Para: joshue.oconnor@cfit.ie; Al Gilman
CC: wai-xtech@w3.org
Asunto: Re: DRAFT response Re[3]: Request for PFWG WAI review of Omitting
alt Attribute for Critical Content


On Thu, 29 Nov 2007 11:59:54 +0100, Joshue O Connor <joshue.oconnor@cfit.ie>
wrote:

> As an aside, while, in principle, I agree that there may be situations 
> where there just is no suitable alternative textual description 
> possible, and the main content whether an image a video object or 
> whatever cannot be described.

I am at a loss to imagine such a situation.

> Then IMO using a alt="" null is fine.

In various cases where an object is described in the rest of the document it
appears in, then indeed there are cases for having alt=""

The flickr examples so commonly given may well be something effectively like

<html xmlns="http://www.w3.org/1999/html">
<head>
   <title>Flickr Photo from Chaals</title> </head><body>
   <h1>Me and my cat playing</h1>
   <p><img alt="" title="photo" src="FYDJ.jpg"/></p>
   <p>tags:</p>
   <ul>
    <li>chaals</li>
    <li>fanstasy</li>
    <li>mog</li>
   </ul>
  </body>
<html>

(for extra points, put an id on the header and make it the longdesc. For
more points, have a real paragraph of description and make that the
longdesc).

This provides the relevant available information (poor, but the kind of
level we see typically). Repeating some of it as the alt is not all that
helpful. In a more complete example, say a movie site, you might have

<html xmlns="http://www.w3.org/1999/html">
<head>
   <title>The Mog - Chaals' Movies</title> </head><body>
   <h1>Playing with the cat</h1>
   <p><img alt="" title="movie in SVG" src="MogMovie.svg"  
longdesc="http://movies.example.org/TheFamousChaalsAndMog"/></p>
   <p>tags:</p>
   <ul>
    <li>chaals</li>
    <li>fanstasy</li>
    <li>mog</li>
   </ul>
  </body>
<html>

The kind of authoring interface that is relevant is one that asks the author
if there is a description already available (URI or click on the description
in the page), and if the image is part of the content (checkbox).

Where there is not enough information available to replace the image, such
as a key graph presented in a report, then having no alt is better than
alt="" - although it fails the testable validity requirement of having alt,
this is a warning that there is a more serious problem (which there is). See
ATAG checkpoint 3.4 [1] and associated techniques information [2].

Other relevant information in this (very old) discussion is available in the
ATAG implementation report [3] (This was before W3C had teh CR process, but
is a prototype CR report), the Working draft of the equivalent techniques
for the draft ATAG 2.0 [4] (see B.2.4 and B.2.5 which follows), inter alia.

[1] http://www.w3.org/TR/WAI-AUTOOLS/atag10.html#check-no-default-alt
[2] http://www.w3.org/TR/ATAG10-TECHS/imp3#check-no-default-alt
[3] http://www.w3.org/1999/12/atag-implemented
[4] http://www.w3.org/TR/2007/ATAG20-TECHS/tech2.html#check-no-default-alt

Cheers

Chaals

> In
> short, I would rather see authors _continue_ to use alt instead of 
> them getting the idea that it *may* sometimes be left out.  Even if 
> this *is* the case. I think this is one cowpath worth paving while 
> suitable better methods are developed, if only to avoid somehow subtly 
> devaluing alt in the mind of the author by producing badly authored 
> examples of these edge cases where alt may be omitted in the spec.



--
Charles McCathieNevile  Opera Software, Standards Group
     je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals              Try the Kestrel - Opera 9.5 alpha
Received on Thursday, 29 November 2007 13:10:38 GMT

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