Quiz 1.1.6: A picture requires a thousand words
We are advised to use the longdesc attribute of the image element when charts, illustrations, and other graphic images contain information too complex to be described with simple ALT text. 
The first difficulty with this technique is the need to create an additional page, and to craft a text description of something that is inherently difficult to describe. If it were simple to describe the object or data in words, why would we use a picture anyway? So, we use a picture to ease comprehension, and then need to use words too; a picture plus a thousand words.
A second difficulty with this technique is the different behaviors implemented in various assistive technology. Some screen readers open a new window for long descriptions. Others don’t.
How do today’s screen readers handle the long description attribute that is associated with the image on this page? Test with either this page, or the nearly identical testcase page.
Q. How do today’s screen readers handle the long description attribute? Indicate the screen reader and version.
- A Opens the longdesc page in a new window
- B Navigates to the longdesc page in the same window
BONUS question: Have you ever seen a D-link “in the wild,” or was it just a cockamamie idea of the WAI?
June 12th, 2005 at 6:39 am
not contributing any testing results as such, but just wanted to share that the issue of D-links was brought up at the recent @media2005 conference in London. one of the nicer ideas discussed (I think it was Ian Lloyd himself who suggested it) was to create a more natural D-link (if required) by creating a link in the image’s caption, and not with the W3C’s proposed [d] monstrosity.
June 12th, 2005 at 7:34 am
Thanks Patrick.
That actually makes a subtle, albeit important, point about the longdesc attribute. It is intended solely for assistive technology. It’s not detectable in the normal browser. So, if sighted users can also benefit from the additional description page, some other link must be provided for them. D-links were a proposed method for providing these links, but are now (thank goodness) deprecated in WCAG 2.0.
Ian’s approach is much saner, and one I’ve used from time to time.
June 12th, 2005 at 8:47 am
IBM Home Page Reader 3.0 displays the link above the image in its internal browser window, which is IE. (IE itself does not show the longdesc attribute as a link, however.)
Following the link replaces the same page/window, rather than opening a new window.
I will check Jaws at some point, unless someone else can get there before me!
Also, a minor note that with bar charts in particular, there is an accessible alternative which is quite elegant, over at http://www.standards-schmandards.com/index.php?2005/02/06/14-accessible-bar-chart
Saying that, of course there are other examples which are not as easy to convert into accessible tables or other text, as are bar charts.
June 12th, 2005 at 1:58 pm
IBM Home Page Reader 3.04 behaves much as Anup describes. It does display an added text link in the IE window which says “Image Description.” It also speaks these same words.
Upon returning from the long description page, HPR 3.04 resumes speaking immediately after the image, not from the top of the page.
June 12th, 2005 at 2:02 pm
Jaws 6.1 with IE 6.0 uses behavior “A.”
It announces the graphic as normal, using the ALT text, then adds “left paren press enter for long description right paren.”
Activating that link opens a new window, which is announced as a new window. After listening to the long description, closing the newly opened windos, and returning to the original window, JAWS begins reading from the top of the page as if it were newly loaded.
June 13th, 2005 at 5:47 am
I work for a financial information company and a few of our older pages (from before I started) have D links. Horrible things. We now use longdescs on our charts pointing to the dynamically generated versions containing accessible tabular data.
June 21st, 2005 at 3:49 pm
Bob, please forgive me for “breaking into the middle of this thread” but I could not locate any email link to you.
Thanks for your words about Disabling America. I just read them on the StuffAndNonsense.co.uk Web site (http://www.stuffandnonsense.co.uk/archives/accessibility_and_a_society_of_control.html) and it’s nice to see others relate what I said and add their own to the mix.
Keep up the good work you’re doing on the access-matters site! - Sincerely, Greg Perry
June 25th, 2005 at 7:09 am
Window Eyes 5.0 with IE 6.0
WE does not announce the longdesc link. Nor, does it announce the image. It does speak the image’s ALT text, but with no indication that it is describing an image.
A verbosity setting ( Global / Verbosity… / MSAA / Longdesc ) is not enabled by default. Enabling it makes no difference.
Clearly, I have too little experience with WE to understand this behavior.