- From: John Foliot <foliot@wats.ca>
- Date: Mon, 8 Sep 2008 11:34:04 -0700
- To: "'James Craig'" <jcraig@apple.com>
- Cc: "'Lachlan Hunt'" <lachlan.hunt@lachy.id.au>, <wai-xtech@w3.org>, <public-html@w3.org>
James Craig wrote: > > In this case, no long description is needed. >From your perspective maybe. Perhaps not the best example, but certainly relevant. I wonder aloud how many blind readers following this thread would argue that the fuller explanation of that particular image that I provided was of zero value, especially the description of the mission patch? > Certainly better alt text > should be there, but the point of the image is adequately described by > the title ("Shuttle Atlantis at the Launch Pad, Set for Hubble > Mission") and the caption ("Atlantis' crew, targeted to launch on Oct. > 10, will upgrade the Hubble Space Telescope, extending the life of the > groundbreaking observatory. [link] Hubble Servicing Mission, [link] > Space Shuttle Section"). Yes, the *reason* for the image is clearly there, but a full description of the image is missing - two very separate and different things. We could have an "angels on the head of a pin" discussion about whether or not users would want to know *what* the image is about, but the reality is that it would come down to the individual user. @longdesc provides an unobtrusive method of providing that information, without the "clutter of minutia" argument you make: it provides an option, a choice, to find out more about the image if/when content authors care to share that information. @longdesc does not impose itself on content consumers, but instead avails itself if so desired. The subtlety or this point seems to be missed in this discussion. > It is irrelevant that the image contains two photos from different > perspectives and a graphic of the mission patch. According to whom? I am not being antagonistic here, but where-else (for example) will users get the detailed information that I provided regarding the patch (there *was* a reason I spent the time describing it). The relevancy or irrelevancy of providing information to end users is not for authors to decide: you, as a sighted user can see that patch (and in fact the whole photo collage) and study it or ignore it as you choose - a non-sighted user does not have that ability, and thus they are being short-changed. > It some respects, it > may even be considered a decorative image. All three of those main > sections contain large images that are intended to get the viewer to > click through to the related article, the images are not there for > their own sake. Agreed, they are not - they actually serve multiple functions: they provide a visual 'teaser' to induce readers to find out more, and they serve to be the recipient of the anchor tags. However, while the second and third images (the rings of Saturn's moon, and Tropical Storm Hanna) are probably sufficiently covered by @alt, the detail of the first image, and *especially* the patch, suggests that an additional layer of explanation/description might be appropriate. *IF* I, as an accessibility advocate and responsible government webmaster wanted to meet the letter of the law, and sought to ensure a fuller description of that image, as well as make it the link that it is right now, how would I do it? Focus on the problem, not the specific example I pulled off of the web to try and make this a real discussion. > > Sometimes overly-detailed accessibility is championed at the expense > of usable accessibility. Consider how often you "skim" content > sections. Blind people don't want to be bogged down by minutia any > more than sighted users do. Correct. However, sometimes, just sometimes, they *DO* want to know the minutia of the image, and in that instance, how can we provide it to the non-sighted, without imposing it on everyone else? Currently, we can do it with @longdesc. > > When @longdesc was the best solution, I argued that it should only > rarely be used, specifically in the case of charts and graphs, where > data visualization represents real page content that requires a longer > explanation than @alt will allow. I agree that this is the most useful time to use @longdesc, but do not suggest that it is the *only* time that it can/should be used. Conversely I too counsel that there is such a thing as going over-board, and do not for a minute suggest that every image used on a webpage should have @longdesc. But when it is necessary, there is nothing else currently that will do the same as what @longdesc does. > Even image galleries (such as Flickr or a museum website) should > rarely, if ever use longdesc. Yes, the main point of the content is > the image itself, but that content should be described on the page. In > the case of artwork, this usually provides benefit to non-disabled > users, too. Imagine an image's in-page, visible long description > provides detailed discussion of the artist's intention in his choice > of color, and the form contrast or dynamic angular motion of the > painting. So we return to image galleries again. This is/was covered in the @alt discussion, where, at the end of the day so long as *a* method of linking text to a visual asset is provided then the image could be deemed conformant. Not *always* @alt (although that is the best-practices recommendation), but "when you can't provide @alt" other means now exist to do the linking, and as long as you use one of them, then you are good-to-go. This solution highlights the real answer - choice. @longdesc is and should also be one of those choices... Let's stop arguing about the whether one image can or should have a long description attached, and let's talk about providing choices. @longdesc currently fills a niche that no other element or attribute fills, and for that reason alone it has value. > This kind of detail enlightens all viewers, and it doesn't need to be > visible by default. The web comic, Penny Arcade (It may have been a > different comic), used to have a drop-down section of the page that > had a data table listing characteristics of each pane, including which > characters were visible, the dialog, and any background information > including links to events or jokes in previous strips that may have > been missed by anyone but a regular reader. Though not initially > visible, this information was useful for numerous reasons. See, there's another "choice", that ensures access to fuller information on demand. It doesn't shove it down your throat, it does not impose itself on you, it simply makes it available *if* you, as an individual consumer, wishes to know more. We need lots of elegant solutions like this, and currently @longdesc hints at the ability to be another type of elegant solution. UI's to date haven't taken full advantage of this, but there *is* progress being made, and as Leif pointed out in a separate email, exposing and using @longdesc is fairly easy using JavaScript. Maybe instead of dismissing @longdesc out of hand, smart and talented developers should start exploring creative ways of using @longdesc and share these ideas to the web. There's a pro-active and positive challenge for you! > > 1. It increased the accessibility for blind readership. > 2. I, for example, didn't know most of the character's names, so I > could learn them by looking in the "long description" section. 3. > Google could more accurately index the content of each page, so > people could search for content by a phrase they remembered. > 4. etc. > > All without the use of longdesc. Right, but with a non-trivial amount of developer work, and a significant amount of screen real-estate that may or may not be appropriate in all instances. It is one choice, but only one of potentially many possible choices. > > The "Visual Complexity" gallery <http://www.visualcomplexity.com/vc/> > has loads of examples where, in its original context, each graph or > chart should probably have had used longdesc. On the VC site however, > even though the images are charts and graphs, longdesc is not required > because each item's page discusses the artistic data visualization > technique used, and in the context of the gallery, the detail of the > data itself is irrelevant. Correct - *IN CONTEXT* @longdesc is probably not required for this site, as the point is not to convey the information about the values expressed in the charts, but rather to discuss "artistic visualizations". And yet... Let's look at an example: http://www.visualcomplexity.com/vc/project_details.cfm?id=592&index=592&doma in= "This diagram displays the 20 biggest cross-border sovereign wealth fund deals since 2005. Each line represents a deal, with thickness scaled by value of deal and color the nationality of the primary buyer. The diagram also highlights the financial advisers and lawyers who worked on more than one of the top 20 deals." Now, as a sighted user, I can tell you that, even from a smaller, thumbnail version of the principle image (you know, this one: http://www.visualcomplexity.com/vc/images/592_big01.jpg, the one without so much as an @alt value) that the 3 largest "wealth funds" are Citigroup (the largest) followed by UBS and Merrill Lynch. I wonder if any of the non-sighted readers here knew that?... Cheers! JF
Received on Monday, 8 September 2008 18:34:51 UTC