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PDF accessibility guidelines. WAS: Re: PDF's and Signatures

From: Thompson, Rachel <rsthompson2@ua.edu>
Date: Thu, 22 Jan 2015 09:06:57 -0600
To: Duff Johnson <duff@duff-johnson.com>, "w3c-wai-ig@w3.org" <w3c-wai-ig@w3.org>
Message-ID: <D0E66CCF.5642B%rsthompson2@ua.edu>
Hi, all. 

This is a question I have received several times lately: What
accessibility guidelines should our web teams and instructors follow when
making PDFs available online? It seems like there is not a consensus with
this group (and you are the group I look to for guidance on these issues).
What guidelines have other organizations adopted? Any ideas or feedback
are welcome.


Dr. Rachel S. Thompson
Director, Emerging Technology and Accessibility
Center for Instructional Technology
University of Alabama

-----Original Message-----
From: Duff Johnson <duff@duff-johnson.com>
Date: Thursday, January 22, 2015 at 8:47 AM
To: "w3c-wai-ig@w3.org" <w3c-wai-ig@w3.org>
Subject: Re: PDF's and Signatures
Resent-From: <w3c-wai-ig@w3.org>
Resent-Date: Thursday, January 22, 2015 at 8:47 AM

> I have to disagree slightly with Andyıs claim ­ PDFs *are* covered-by
>and included in WCAG

To a degree, There are many facets of PDF that WCAG does not cover. For a
complete understanding of PDF accessibility it is necessary to look to
PDF/UA, the ISO standard for accessible PDF.

> , and in fact there is a whole section of Success Techniques provided by
>the W3C. Please see: http://www.w3.org/WAI/GL/WCAG20-TECHS/pdf.html

While many of these are useful, some are simply wrong, misleading, or
both. Additionally, these techniques represent only a modest fraction of
whatıs necessary to guarantee an accessible PDF.

> I think the issue(s) you will find problematic include how to render
>that wet signature to non-visual users (itıs not text, so OCR etc. will
>struggle to dealinclude a graphic of a signature, you will of course need
>to also provide appropriate alt text (I would likely counsel this:
>alt=²[Signature: Mickey Mouse]²)

One must distinguish between an ink signature (which is simply a graphics
object requiring alt text to be accessible) and a digital signature, which
is a property of the document itself, and should be exposed by AT
accordingly just as is other document metadata.

> I am personally unaware of the current state of accessibility and
>digital signatures on PDFs, although my first guess is that it is likely
>not perfect, buta robust and long-standing (if still imperfect) tool in
>their shed. Perhaps Andrew might have a comment here (?)

So far as I am aware the digital signature UIs in Adobeıs tools are as
accessible as the rest of Adobe Acrobat / Readerıs UI. This has *nothing*
to do, however, with an ³ink² signature, which is simply a pretty picture
on the page, and like all other pictures, needs alt text to expose it to
all forms of AT equally.

Received on Thursday, 22 January 2015 15:07:54 UTC

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