- From: Robert J Burns <rob@robburns.com>
- Date: Tue, 13 May 2008 22:13:16 +0000
- To: Maciej Stachowiak <mjs@apple.com>
- 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
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 link’s 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 element’s 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