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Re: HTML Action Item 54 - ...draft text for HTML 5 spec to require producers/authors to include @alt on img elements.

From: Robert J Burns <rob@robburns.com>
Date: Tue, 13 May 2008 22:13:16 +0000
Cc: Steven Faulkner <faulkner.steve@gmail.com>, Andrew Sidwell <w3c@andrewsidwell.co.uk>, "public-html@w3.org Group" <public-html@w3.org>, W3C WAI-XTECH <wai-xtech@w3.org>, wai-liaison@w3.org
Message-Id: <B14961A7-742F-48E4-8725-197B17C60999@robburns.com>
To: Maciej Stachowiak <mjs@apple.com>

Hi Maciej,

On May 13, 2008, at 6:23 PM, Maciej Stachowiak wrote:

>
>
> On May 13, 2008, at 11:09 AM, Steven Faulkner wrote:
>
>>> the AI54 proposal says non-empty alt is mandatory for any image that
>> is not purely decorative.
>>
>> well no it does not, it does not MANDATE anything as it clearly  
>> states
>> that the advice in informative not normative.
>
> It does have the following mandatory conformance requirements:
>
> "The alt attribute must present and must contain a text alternative  
> that serves the equivalent purpose as the image. What is to be  
> considered an equivalent purpose, depends on the way an image is  
> used."
>
> Then the advice expands on what is considered equivalent for  
> different uses of images. The only case where empty alt is suggested  
> is for purely decorative images.
>
> Robert said: "According to the new draft section, the alt attribute  
> is not to be used for description of photographs that are critical  
> content."
>
> Would you agree with Robert's interpretation of the AI54 proposal  
> (this is what he meant by "the new draft section")?

You are correct. I got that part of the proposal wrong. I was thinking  
it aligned more with my views on this which is that we should use  
separate syntactic mechanisms to describe photographs than we use to  
provide the alternate equivalent text. One problem with not separating  
these mechanisms more arises in the iPhoto / dot Mac example I  
described. In that example the image is used both as a link and is  
also a photograph so, in the current proposal, it would require both a  
description of the linkís purpose and a description of the photo  
(which I think can be awkward).

As you quoted from the proposed language:

> "Appropriate alt text value for a picture is a brief description, or
> name. As in all alt text authoring decisions, writing suitable text
> equivalents for pictures requires human judgment. The alt text value
> is subjective to the context where the image is used and the page
> author's writing style."
>
> The example given is:
> <figure>
> <img src="1100670787_6a7c664aef.jpg" alt="My dog, Bubbles, digging in
> the sand on the beach">
> <legend>Bubbles traveled everywhere with us.</legend>
> </figure>

On dot Mac it would require something instead like

<a href='somelink' ><img src="1100670787_6a7c664aef.jpg" alt="My dog,  
Bubbles, digging in
the sand on the beach; a link back to the gallery page"></a>

but instead could be:

<a href='somelink' alt='a link back to the gallery page' ><img  
src="1100670787_6a7c664aef.jpg" alt="My dog, Bubbles, digging in
the sand on the beach"></a>

or:

<a href='somelink' alt='a link back to the gallery page' ><img  
src="1100670787_6a7c664aef.jpg" title="My dog, Bubbles, digging in
the sand on the beach"></a>

To me this underscores the need to perhaps separate things further.  
One approach could be to add @alt to the A element and require  
conforming documents either have text content within the A element or  
provide text within the A elementís alt attribute. Another approach  
that I have advocated is that photographs (at least in the vast  
majority of photographs) require null alt just like decorative images  
(i.e., alt=''). This is the one point of departure I have with the  
current proposal. I think instead the title attribute of the IMG  
element would be an appropriate place to reflect the title of the  
photograph (especially if it is a human generated descriptive title  
and not a machine generated title). However, I feel that longdesc, and  
aria-described-by are better mechanisms for describing a photograph  
beyond simply a descriptive title. On the other hand, with a chart, or  
graph, an image of a map I feel it is appropriate to use the alt  
attribute to describe those images (as the current proposal lays out).

To me it is important to have alt required as a gateway drug (so to  
speak) into accessibility authoring and that secondly, it only be used  
for relatively precise and brief text alternatives. A photograph is  
not necessarily something that can be described briefly and precisely  
(ask two people to describe a photograph and you'll get 12 answers).

In the case of photographs and other such meaningful images it is more  
important to let users know that the image is there (for download,  
processing or some other awareness), but not as crucial to have  
alternate text describing the photo. Your @noalt proposal or  
role='meaningful' would both be suitable approaches to provide a  
syntax to differentiate photographs from decorative images  
(ultimately, it would be best to only include decorative images  
through CSS leaving only photographs and similar images for an alt  
attribute null value).

Take care,
Rob
Received on Tuesday, 13 May 2008 22:14:04 UTC

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