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Re: alt and authoring practices

From: Steven Faulkner <faulkner.steve@gmail.com>
Date: Wed, 16 Apr 2008 12:23:06 +0100
Message-ID: <55687cf80804160423k26f470c2h824d227331764505@mail.gmail.com>
To: "Anne van Kesteren" <annevk@opera.com>
Cc: "James Graham" <jg307@cam.ac.uk>, public-html@w3.org, wai-xtech@w3.org, wai-liaison@w3.org

Hi Anne,
I don't quite follow the logic, but that is probably due to my
incapacity to understand, but I am pretty sure you are making a
worthwhile point and will cogitate on it further.

> With nobody having data of usage on the Web the position of the editor seems
> more reasonable to me.

And that is your prerogative as a member of the working group, I
myself do not place faith in the editor as being all seeing and all
knowing in the absence of data.

regards
steve

On 16/04/2008, Anne van Kesteren <annevk@opera.com> wrote:
> On Wed, 16 Apr 2008 12:32:59 +0200, Steven Faulkner
> <faulkner.steve@gmail.com> wrote:
> > Take the example of the john's flickr page cited by Ian earlier, that
> > page contained 24 images without an alt attribute. There is no
> > reliable means to determine whether any of these images contain
> > information important enough "critical to understanding the page" to
> > convey their presence to the user. If all our conveyed in some way,
> > the user would hear the word "graphic" (for example) 24 times
> > sprinkled throughout the text content of the page, adding to the
> > cognitive load on the user without aiding understanding. To get any
> > information from these images, the user would have to set "virtual"
> > focus to each one in turn (for example in JAWS, users can navigate
> > from image to image using the G key) and then use a series of
> > keystrokes to query the attribute values (src for example).  In most
> > cases the attributes will not contain any useful information, so would
> > be an exercise in futiltity for the user. As well as taking a very
> > long time.
> >
> > does that help?
> >
>
> What do you base the assumption on that when pages omit the alt attribute
> they likely mean setting it to the empty string where as they have the alt
> attribute it likely is correct? If you want to consider non-conforming pages
> in this debate and it seems you do you really have to consider the
> likelyhood of all the mistakes that could be made.
>
> For alternate text we have three types of images: Images for which there's
> alternative text (available). Images for which there's no alternative text
> (missing). Images for which the alternative text is the empty string
> (empty).
>
> Current authoring practices have these three variants: <img alt="...">, <img
> alt="">, and <img>.
>
> Given that authors make mistakes there are nine possibilities of authoring
> images:
>
>  1. <img alt="..."> - available -> Correct usage
>  2. <img alt=""> - available -> Incorrect usage
>  3. <img> - available -> Incorrect usage
>  4. <img alt="..."> - missing -> Incorrect usage
>  5. <img alt=""> - missing -> Incorrect usage
>  6. <img> - missing -> Correct usage
>  7. <img alt="..."> - empty -> Incorrect usage
>  8. <img alt=""> - empty -> Correct usage
>  9. <img> - empty -> Incorrect usage
>
> It seems your assumption is that on average 9 is more common than 3 and 6
> combined and that therefore <img> should be equivalent to <img alt=""> as
> far as user agents go and we should have an alternative solution to cater
> for 6.
>
> It seems the assumption from the editor is that on average all incorrect
> usage is about as likely and that therefore 3 and 6 should win from 9 and
> that therefore <img> might as well be used for this case.
>
> With nobody having data of usage on the Web the position of the editor seems
> more reasonable to me.
>
>
> --
> Anne van Kesteren
> <http://annevankesteren.nl/>
> <http://www.opera.com/>
>


-- 
with regards

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

www.paciellogroup.com | www.wat-c.org
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Received on Wednesday, 16 April 2008 11:23:44 UTC

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