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Re: PDF U/A alternate description for links

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From: chagnon@pubcom.com
Date: Feb 15, 2023 7:34AM

This is an error in PDF/UA, and as a member of the ISO committee that writes PDF/UA, I believe that it's the type of requirement that committee members don't fully understand. (The original standard was written before I joined the committee.)

Software checkers like PAC, Adobe's accessibility checker, CommonLook, etc. can only determine yes/no situations, such as "yes" the link has Alt Text or "no" it doesn’t. It takes a human being to determine whether it's needed or not, not software.

Several of the software remediation tools flag missing Alt Text as an error, and then provide the software solution — which just picks up the hyperlink text and repeats it as Alt Text. How is that supposed to benefit the end user? It's repeating the same information but without the user controls of regular text: Screen readers clip the user's control when reading Alt Text.

We use PAC 3 to flag hyperlinks and then manually check them to determine if Alt Text is warranted. Definitely do not put Alt Text on TOCs because it clips the user's control over what they hear and how it's presented to them. Functionality is diminished.

We need to do better.

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Bevi Chagnon | Designer, Accessibility Technician | <EMAIL REMOVED>
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PubCom: Technologists for Accessible Design + Publishing
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-----Original Message-----
From: WebAIM-Forum < <EMAIL REMOVED> > On Behalf Of Elizabeth Thomas
Sent: Tuesday, February 14, 2023 1:34 PM
To: WebAIM Discussion List < <EMAIL REMOVED> >
Subject: [WebAIM] PDF U/A alternate description for links


I have a question about alternate descriptions for links and was unable to find an answer online; I thought someone on this list must know the answer.
Why does PDF U/A require alternate descriptions for links? If my link is human readable, and makes sense out of context, why do I also need an alternate description for that link? It seems like the rule should only apply to badly written links or full URLs.
For example, if the link text in my PDF is the web page title, and that text is a content object that is a child of the link, won’t technologies associate that text with the link? And won’t assistive technologies, like a screen reader, read that text when they encounter the link?
Are there some technologies that don’t correctly read the associated text when they encounter a link? Is that what the standard is addressing?
I know how to automate adding the alternate descriptions for links in a PDF, but it seems unnecessary (unless the links are full URLs or don’t describe the link destination when taken out of context). PAC 3 always flags this issue, but I don’t really understand why it’s in the guidelines/standards.
Thanks in advance.
-Elizabeth Thomas
Digital Accessibility Specialist
New Jersey Department of Education