W3C home > Mailing lists > Public > public-comments-wcag20@w3.org > October 2008

Re: Image use cases that WCAG doesn't address

From: Henri Sivonen <hsivonen@iki.fi>
Date: Fri, 31 Oct 2008 18:45:57 +0200
Cc: public-comments-wcag20@w3.org
Message-Id: <4A75253F-78D4-4E31-8DA8-1D6A0E1196C6@iki.fi>
To: Gregg Vanderheiden <gv@trace.wisc.edu>


Thank you for your reply to my feedback.

On Oct 30, 2008, at 19:12, Gregg Vanderheiden wrote:

> The question arises as to when it is important for users to access  
> information or functionality that is in non-text content.

I wasn't in any way contesting the importance for users.

> Redundant
> Our Guidelines require that a short alternate text be provided  
> identifying the non-text content, describing it or telling the user  
> where they can find the longer description.  For example   "Sales  
> chart - described at bottom of page" or  "Sales chart - described in  
> 2nd paragraph following".    Some have felt that no alt text was  
> required if there was equivalent text on the page.   Others found  
> that it was very confusing when they encountered non-text content  
> but did not know whether it contained information that was not  
> otherwise in the text of the page.   Others had problems when people  
> referred to a diagram on the page, for instance, and they did not  
> know that the page contained a diagram or what it was about.

This makes sense and addresses my first point. Thank you.

(I'll relay this point to the editor of HTML 5 as well, since the  
examples in HTML 5 may not be fully aligned with your examples.)

> Content beyond Author Control
> You also raised the question of content that will be added later,  
> where the author doesn't have any control of the content and cannot  
> add meaningful alternate text.  We recognize this situation and have  
> provided a concept called a  "Statement of Partial Conformance".    
> This allows authors to be able to make a statement about the page  
> that does not include the content they can't control.   They can't  
> claim the page conforms, because part of it may not.  But they can  
> state that the page would conform if that uncontrolled part is not  
> there.   We took this approach because we didn't want users to  
> encounter conforming pages that still contained  information that  
> was not accessible.  On the other hand we wanted a means to  
> recognize pages where the authors have made the page as conformant  
> as possible.

My concern wasn't about being able to claim conformance to WCAG when  
the content is not accessible. I'm OK with developers of e.g. photo  
gallery software claiming Partial Conformance when the actual  
accessibility of the output of the software depends on cooperativeness  
of the human supplying input to the software.

My concern was about ATAG by reference to WCAG effectively encouraging  
software developers to make up a bogus text alternative when the  
software (for whatever reason) didn't get a text alternative from a  
human operator.

> If these and our previous comments address your concerns please let  
> us know.    If not, we would like to meet with you and discuss them.
> I know that your working group likes to work asynchronously but if  
> we could arrange a meeting with you and Mike Smith to explore these  
> issues we think it would be productive.
> As we need to move forward with WCAG, could you please email or call  
> us this week and let us know if you are OK with the WCAG WG's  
> response? If you are satisfied, but would still like to meet later  
> to explore the topics above, we would also be interested in that. If  
> you are not satisfied, you of course have the option of filing a  
> formal objection, but we would need this right away.

I think my first concern ("A diagram illustrates what is already said  
textually.") was addressed in your email even though I am still unable  
to arrive at the same conclusion by reading the WCAG 2.0 spec text  
independently. (The spec text didn't change, after all.)

I think my second concern ("A user-uploaded image whose content is  
unknown to the programmer of the HTML generator that frames the image  
for Web display and the user hasn't supplied a text alternative.") was  
addressed in your email on the level of what to do about claiming  
conformance, but it wasn't addressed on a practical level in such a  
way that a software developer with normal reading comprehension skills  
trying to comply with ATAG 2.0 and following a normative reference  
from ATAG 2.0 to WCAG 2.0 would merely by independently reading what  
the spec says (without access to interpretations from spec authors)  
arrive at the conclusion that ATAG and WCAG taken together mean that  
(s)he shouldn't make up a bogus placeholder text alternative when none  
is otherwise available.

(If I identified the added technique correctly, it pertained to an  
example in the HTML 5 draft but not to the two specific concerns I had.)

I don't wish to file a formal objection, but I am interested in  
discussing my second concern further, and I would prefer it to be  
addressed more explicitly and obviously. ATAG 2.0 might be a better  
place than WCAG 2.0 for addressing it, though.

Henri Sivonen
Received on Friday, 31 October 2008 16:46:39 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:14:50 UTC