W3C home > Mailing lists > Public > public-html@w3.org > May 2008

Re: alt and authoring practices

From: Robert J Burns <rob@robburns.com>
Date: Sat, 3 May 2008 22:27:01 +0000
Message-Id: <CD2E404A-1CFC-4F18-AF16-F2DF32C8CB79@robburns.com>
To: "HTML Working Group <public-html@w3.org>" <public-html@w3.org>


On May 3, 2008, at 2:37 PM, Smylers wrote:

>>
>> iPhoto allows me to add descriptions to my photos and give them
>> appropriate titles. However, that information remains in the image
>> supported metadata (inside the jpeg file) ... it may be cumbersome  
>> for
>> (author) to provide descriptions of every photo of hundreds uploaded
>> to the web.  However, it is even more disappointing for an author who
>> has already included such descriptions to have their authoring tool
>> leave them out of the generated content.
>
> Yes.  In those cases the descriptions are available to the software
> generating the page, so the images are not 'unknown'; it should
> therefore use those descriptions.
>
> (If they are indeed descriptions; you initially mention "titles"  
> above.
> Photos may be given titles (captions) which are intended for those who
> can already see the photos; they may be humourous or cryptic or
> whatever, and in no way describe what can be seen in the photos.  In
> that case the titles would be poor alternative text.  And anyway  
> they'd
> probably already be included elsewhere on the page, such as as visible
> captions.)
>

>> Again, this has nothing to do with the @alt attribute however.
>
> Well if descriptions are available then surely they should be in the  
> alt
> attribute?


Regarding mandatory alt attribute, this response reflect the same  
misunderstanding I've been trying to correct[1], so let me respond to  
it directly.

No! Descriptions of the photograph in this scenario do not belong in  
the alt attribute. This is a fundamental misuse of that attribute  
(according to the best practice so many have tried to describe here).  
The description metadata for a photograph properly belongs in the  
media file's metadata or pre-extracted by the author and authoring  
tools and placed in a referenced document fragment (referenced either  
with longdesc or aria:described-by attributes to name a few). Filling  
the alt attribute with descriptions of a photograph is inappropriate.

One source of the miscommunication here may be in the HTML5's draft's  
current state. Right now it has no @longdesc attribute, so one might  
read that as implying that anything descriptive about the photograph  
belongs in the @alt. If that's what the editor intended, then that  
opens up other problems (including problems with current practice and  
the web as it exists now). Once descriptions of the photograph are  
handled elsewhere, there's very little left in this disagreement that  
has raged on for months upon months.

To summarize:
• @alt: a textual alternate, indispensably substituted for the image  
in cases where the user or user agent is unable to retrieve or  
otherwise consume the resource
• media format metadata: for descriptions, titles, coverages,  
copyright notices, licenses, etc. (ideally UAs would make some or all  
of this available to users in browsing situations)
• document fragment referenced through @aria:described-by or  
@longdesc: a good place for authors and authoring tools to extract a  
description of the photograph for user agents unable to do it themselves

So much of the talking past one another is due to some trying to make  
@alt serve all of these roles and therefore making it mandatory is  
cumbersome. On the other hand others want to maintain a mechanism in  
HTML for referencing semantically rich descriptions of embedded media  
(e.g., @longdesc) and therefore requiring alt for all images (even if  
it's only alt='') is not cumbersome, nor destructive to accessibility,  
at all.

Imagine a situation where I ask a vision impaired colleague to  
download the image from my iPhoto web gallery: ‘IMG_0301’.  What text  
alternates would be required for such a vision impaired (or totally  
blind) user to perform such an operation. The full description may be  
included in the image file itself and the description may even be  
referenced by @longdesc in a separate document fragment. None of that  
makes the page more usable in this situation. What allows the user to  
view the download the photo is properly provided alt text: the same  
alt text I suggested in my earlier example (e.g., ‘ alt='view image  
&quot;IMG_1234&quot; fullsize' ’). (BTW, I know my galleries include  
the title of the photo anyway, but that's an optional checkbox in  
iPhoto since some users do not want those cryptic looking titles  
marring the page).

Take care,
Rob

[1]: <http://lists.w3.org/Archives/Public/public-html/2008May/ 
0034.html>,
      <http://lists.w3.org/Archives/Public/public-html/2008May/ 
0039.html>
      <http://lists.w3.org/Archives/Public/public-html/2008May/ 
0040.html>
      <http://lists.w3.org/Archives/Public/public-html/2008May/ 
0047.html>
Received on Saturday, 3 May 2008 22:27:39 UTC

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