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Thread: Longdesc vs d
Number of posts in this thread: 11 (In chronological order)
From: ED COHEN
Date: Tue, Oct 28 2003 7:27AM
Subject: Longdesc vs d
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Hello All,
This group is so helpful!
Our state agency is moving towards producing 508 compliant pages. We are also working up a plan to repair the almost 10,000 old non-compliant pages we currently offer.
Our question is how long, if at all, should we plan to use the "d" for complex graphics, since newer screen readers do support the "longdesc" tag?
Should we be concerned about consistency... offering the d on some pages but not on others?
How are others dealing with this
From: julian.rickards
Date: Tue, Oct 28 2003 7:38AM
Subject: RE: Longdesc vs d
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Hi Ed:
What I do is to divide the graphics into three categories: decorative,
simple and complex. Decorative graphics are those that provide no content
value to the page and are given alt="" or if possible, I try to make them a
background graphic using CSS. Simple graphics are those which do provide
content to the page and I put a short alt (generally no more than 6 words)
to describe the graphic. Complex graphics I haven't encountered yet on my
site (or at least the portion I am responsible for) but I envision things
like charts or graphs as being complex graphics which requre a "d" link. As
for consistency, for me, this is a consistent policy.
As to how long we will be needing the "d" link? How long have we been
waiting for NN4.x to disappear off the browser charts so that we don't have
to jump through hoops to ensure users of that browser don't crash when
viewing your pages, even if the look or style is not the same as current
browsers. I don't know that anyone can answer that but there may be some
clues in JAWS 5.0 as to whether or not the longdesc attribute is supported.
Jules
---------------------------------------------------------
Julian Rickards
Digital Publications Distribution Coordinator
Publications Services Section
Ontario Ministry of Northern Development and Mines
Phone: (705) 670-5608
Fax: (705) 670-5690
From: ruth_k_marshall
Date: Tue, Oct 28 2003 7:43AM
Subject: Re: Longdesc vs d
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Hi Ed,
I refer to the Royal National Institute of the Blind's (RNIB) web page at
http://www.rnib.org.uk/xpedio/groups/public/documents/publicwebsite/public_wac_waicheckpoints.hcsp
and in particular checkpoint 1, Provide a text equivalent for every
non-text element (WAI 1.1).
RNIB recommend that a longer description of the image is provided in text
accompanying the image or that an alternative link to a separate page
containing information about the image is conveyed. The HTML "longdesc"
attribute can be added to the image code, linking to the same page but like
you say, not all browsers support this attribute. If you choose to
continue using this attribute it should not be used as a sole means of
linking to a page which has information on the content of the image.
Regards, Ruth
Ruth Marshall
The Standard Life Assurance Company
Dundas House
Group E-commerce Development
1st Floor
20 Brandon Street
Edinburgh
EH3 5PP
Tel: 0131 246 6376 ext 66376
Email: = EMAIL ADDRESS REMOVED =
Web: www.standardlife.com
webaim-forum-requ
= EMAIL ADDRESS REMOVED = .o To: < = EMAIL ADDRESS REMOVED = >
rg cc: (bcc: Ruth K Marshall/STANDARD LIFE ASSURANCE COMPANY)
bcc: Ruth K Marshall/STANDARD LIFE ASSURANCE COMPANY
28/10/2003 14:20 Subject: Longdesc vs d
Please respond to
webaim-forum
Hello All,
This group is so helpful!
Our state agency is moving towards producing
From: Jukka K. Korpela
Date: Tue, Oct 28 2003 7:44AM
Subject: Re: Longdesc vs d
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On Tue, 28 Oct 2003, ED COHEN wrote:
> Our question is how long, if at all, should we plan to use the "d" for
> complex graphics, since newer screen readers do support the "longdesc"
> tag?
You should use neither. Neither of them is required by 508 rules, and
neither of them is useful for actual accessibility.
Some people may say that such constructs are useful to _some_ people,
depending on their browsers and on their comprehension and guessing
skills (how many people intuitively understand the meaning of "[D]"?).
But wasn't accessibility supposed to mean accessibility to _all_?
For a complex graphic that has essential content expressible in words,
use a normal textual link to page that contains the verbal alternative.
You can often turn an image caption into such a link, but if needed,
simply include a separate link, like "A <a href="...">textual description
of our organization</a> is available, too".
Note that using several links with the same link text but pointing to
different locations (which is an inherent feature of the "[D]" link
technique) definitely violates WCAG checkpoint 13.1 as refined in the
associated HTML techniques document.
--
Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/
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From: Michael D. Roush
Date: Tue, Oct 28 2003 9:03AM
Subject: Re: Longdesc vs d
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First of all, let me offer my congratulations to your agency for taking the
step of proactively seeking to make your pages accessible! You are right
about the quality of the exchange of information on this list. I forgot how
much I missed it while I was away from it.
Now, about 'd-link' vs. 'longdesc'. As the story has been told to me (and
some research seems to verify), 'd-link' was designed as an intetrim
solution, between the time 'longdesc' was put up as a recommendation and
browser support for it becomes widespread. It seems to have come from the
good folks at WGBH/NCAM. And, as I said, it was designed to be a temporary
solution, until 'longdesc' comes of age.
I found this in Checkpoint 1.1 of the WCAG:
"For complex content (e.g., a chart) where the "alt" text does not provide a
complete text equivalent, provide an additional description using, for
example, "longdesc" with IMG or FRAME, a link inside an OBJECT element, or a
description link [this is a reference to the d-link system]."
Now, you mentioned trying to comply with Section 508, not specifically
mentioning the WAI. Section 508 specifically mentions using 'longdesc' but
not the 'd-link' technique. But, an argument could be made that a 'd-link'
keeps the spirit of the standard, and the list of examples given wasn't
meant to be exhaustive, or even that a 'd-link' qualifies as 'element
content' which is specifically mentioned. So, I'm not sure that the 'use
neither, because they aren't standard' suggestion holds. There is a bit of
double edged sword to using one or both, though. Using one will likely
leave those who routinely use the other a bit confused or left out. But
using both may make both groups confused! Since you have so many pages, and
the 'd-link' was suggested as an interim solution (if you take it as a valid
suggestion to begin with! Some don't.), I would not decide to add any more
d-links than you currently have, and work towards going to using 'longdesc'.
Otherwise, you are going to have a bunch of d-links you added recently to
get rid of once 'longdesc' support is better - and it will get better sooner
if more people use them. Only very complex images requiring longer
descriptions would be good candidates for the 'longdesc' (and likewise, a
'd-link'), so there may not be a large number of them even on such a large
website. The bigger issue over 'consistency' is probably alerting users
what the little 'd' means, since the practice is not in great wiidespread
use, most people still have no idea what it is.
My suggestion would be to develop an accessibility policy and then stick
with it. You have a lot of archive pages to deal with. Ten thousand pages,
updated at 40 per week, would take you 5 years to accomplish. By then, I
imagine lots of things will change. So, perhaps something like:
"The Indiana Department of Environmental Management is committed to
providing accessible content to our users. New pages are designed to adhere
to US Federal Rehabilitation Act Section 508 standards for accessibility.
Older pages are in the process of being updated to comply with these
standards...(insert your criteria for updating pages and which pages you
won't update here)."
Then you have something to guide you as you look through those old pages.
Michael
----- Original Message -----
From: ED COHEN
To: = EMAIL ADDRESS REMOVED =
Sent: Tuesday, October 28, 2003 9:20 AM
Subject: Longdesc vs d
Our question is how long, if at all, should we plan to use the "d" for
complex graphics, since newer screen readers do support the "longdesc" tag?
Should we be concerned about consistency... offering the d on some pages but
not on others?
----
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visit http://www.webaim.org/discussion/
From: Paul Bohman
Date: Tue, Oct 28 2003 10:20AM
Subject: Re: Longdesc vs d
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To echo what Jukka said, here is a quote from the WebAIM tutorial on
accessible images (found at http://www.webaim.org/techniques/images/6):
<quote>
6.2 Methods of Providing a Long Description
There are several ways of providing a long description for images. I
have listed these options below, in order of "most preferred" first to
"least preferred" at the bottom:
1. Provide the long description in the context of the document itself
2. Provide a link to a long description via a normal text link
3. Provide a link to a long description via the longdesc attribute
4. Provide a link to a long description via a "d" link
Those who are familiar with accessibility techniques may be surprised to
find that the longdesc attribute and "d" link are at the bottom of the
list. The reason for this is that both methods are rather obscure. The
longdesc attribute is invisible (and inaccessible in some browsers) to
people who are not using screen readers. The "d" link is
non-conventional, and can be confusing to people who are not familiar
with their purpose. The most straightforward way of making long
descriptions accessible is to make them obvious and available to
everyone, whether or they have a disability or not.
</quote>
--
Paul Ryan Bohman
Technology Coordinator
WebAIM (Web Accessibility in Mind)
www.webaim.org
Center for Persons with Disabilities
www.cpd.usu.edu
Utah State University
www.usu.edu
Jukka K. Korpela wrote:
> On Tue, 28 Oct 2003, ED COHEN wrote:
>
>
>>Our question is how long, if at all, should we plan to use the "d" for
>>complex graphics, since newer screen readers do support the "longdesc"
>>tag?
>
>
> You should use neither. Neither of them is required by 508 rules, and
> neither of them is useful for actual accessibility.
> ...
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From: Jared Smith
Date: Tue, Oct 28 2003 10:55AM
Subject: Re: Longdesc vs d
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Another very logical way to give access to the long description is by
making the complex image itself a link to the long description page.
If the textual description is on another page, then I'd still add the
longdesc attribute, but also make the image a link to the same
longdesc page. This solves the problems of lack of longdesc support,
the obscurity of the d link, and does not require other visible text
on the page.
<a href="longdesc.htm"><img src="compleximg.gif"
alt="Pie chart showing number of visitors with link to more information"
longdesc="longdesc.htm"></a>
Also, the long decription page does not have to be text only. The page
can still contain colors, layout, and (heaven forbid) more images, as
long as it provides the description of the complex image in an
accessible manner.
Jared Smith
WebAIM (Web Accessibility In Mind)
Center for Persons with Disabilities
Utah State University
***************
On Tuesday, October 28, 2003 you sent:
PB> To echo what Jukka said, here is a quote from the WebAIM tutorial on
PB> accessible images (found at http://www.webaim.org/techniques/images/6):
PB> <quote>
PB> 6.2 Methods of Providing a Long Description
PB> There are several ways of providing a long description for images. I
PB> have listed these options below, in order of "most preferred" first to
PB> "least preferred" at the bottom:
PB> 1. Provide the long description in the context of the document itself
PB> 2. Provide a link to a long description via a normal text link
PB> 3. Provide a link to a long description via the longdesc attribute
PB> 4. Provide a link to a long description via a "d" link
PB> Those who are familiar with accessibility techniques may be surprised to
PB> find that the longdesc attribute and "d" link are at the bottom of the
PB> list. The reason for this is that both methods are rather obscure. The
PB> longdesc attribute is invisible (and inaccessible in some browsers) to
PB> people who are not using screen readers. The "d" link is
PB> non-conventional, and can be confusing to people who are not familiar
PB> with their purpose. The most straightforward way of making long
PB> descriptions accessible is to make them obvious and available to
PB> everyone, whether or they have a disability or not.
PB> </quote>
***************
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From: John Foliot - WATS.ca
Date: Tue, Oct 28 2003 11:10AM
Subject: RE: Longdesc vs d
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Hi Ed,
Jukka's point about multiple D Links is valid if you plan on having more
than one image on a "page", but outside of that, providing d links to my
mind still has some merit. Depending on the amount of flexibility you have
(i.e. once you understand the rules, can you break some?) might I suggest
you look at the following: http://wats.ca/resources/longdesc/31 which
demonstrates implementation of LONGDESC as well as a method of providing d
links to *some* users.
JF
--
John Foliot = EMAIL ADDRESS REMOVED =
Web Accessibility Specialist / Co-founder of WATS.ca
Web Accessibility Testing and Services
http://www.wats.ca 1.866.932.4878 (North America)
From: julian.rickards
Date: Tue, Oct 28 2003 11:27AM
Subject: RE: Longdesc vs d
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As a result of the FIR technique, a number of people have been exploring the
accessibility of such a technique including Joe Clark's article at
http://www.alistapart.com. It has since been discovered that screen reader
support for display:none and visibility:hidden is confusing at best. In the
tutorial you provided a link to, you suggest the use of text the same color
as the background which "hides" the "d" link (visibly anyway). Has anyone
tested to see if text hidden in this manner is available/unavailable to JAWS
just like display: none and visibility: hidden?
There may be a way out though - JAWS doesn't "see" styles that are imported
so one could create a rule in an imported stylesheet.
Jules
---------------------------------------------------------
Julian Rickards
Digital Publications Distribution Coordinator
Publications Services Section
Ontario Ministry of Northern Development and Mines
Phone: (705) 670-5608
Fax: (705) 670-5690
From: julian.rickards
Date: Tue, Oct 28 2003 1:15PM
Subject: RE: Longdesc vs d
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Good to know!
Thanks Larry.
---------------------------------------------------------
Julian Rickards
Digital Publications Distribution Coordinator
Publications Services Section
Ontario Ministry of Northern Development and Mines
Phone: (705) 670-5608
Fax: (705) 670-5690
>
From: Stephanie Sullivan
Date: Thu, Oct 30 2003 9:16AM
Subject: Re: Longdesc vs d
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on 10/28/03 1:18 PM, = EMAIL ADDRESS REMOVED = at
= EMAIL ADDRESS REMOVED = profoundly spewed forth their very articulate
thoughts:
> It has since been discovered that screen reader
> support for display:none and visibility:hidden is confusing at best. In the
> tutorial you provided a link to, you suggest the use of text the same color
> as the background which "hides" the "d" link (visibly anyway).
I would NOT recommend text the same color as the background. This is seen as
spamming by most search engines since people used to hide keywords all over
their pages that way... It can be detrimental and even cause your page to be
blacklisted.
Stephanie Sullivan
Contributing Author .: "Macromedia Dreamweaver MX 2004 Magic" :. New Riders
CommunityMX Team Member :: http://www.communitymx.com
Technical Editor .: "DreamweaverMX Killer Tips" :. New Riders
VioletSky Design :: http://www.violetsky.net