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

From: Jonathan Avila <jon.avila@ssbbartgroup.com>
Date: Thu, 22 Jan 2015 15:48:34 +0000
To: "Thompson, Rachel" <rsthompson2@ua.edu>, Duff Johnson <duff@duff-johnson.com>, "w3c-wai-ig@w3.org" <w3c-wai-ig@w3.org>
Message-ID: <BY2PR03MB27235FE02A3242714E34F969B490@BY2PR03MB272.namprd03.prod.outlook.com>
> What accessibility guidelines should our web teams and instructors follow when making PDFs available online?

Duff's 2012 article on the relationship between WCAG and PDF/UA is still relevant and may help you make  determinations on what standards to follow.  

Right now in a practical sense there are a limited number of accessible PDF readers and a limited number of conforming assistive technologies -- so WCAG guidelines are likely to be sufficient as long as sufficient techniques used to meet the success criteria are accessibility supported.  That's also one area where PDF/UA will in the future play a more important role.

WCAG also tends to go into more details on what is really required when color is used -- e.g. that you must have a visual and text/programmatically way to communicate the use of color.  IMO the PDF/UA is a little weak in this are implying that programmatic alternatives will suffice.  In practical sense this could work if user agents exposed programmatic information to users who are colorblind but don't use assistive technology but this isn't the case.  Similarly, IMO the PDF/UA requirements for multimedia don't go into all of the requirements for accessible multimedia in way that is practically needed to ensure captions and audio description are synchronized and truly provide equivalents.  But I don't think the goal of PDF/UA was duplicate WCAG -- it grew up alongside WCAG 2 and provide sufficient techniques that can be used to determine conformance and provides details on contracts between conforming user agents in way similar to the UAAG.


Jonathan Avila
Chief Accessibility Officer

703-637-8957 (o) 
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-----Original Message-----
From: Thompson, Rachel [mailto:rsthompson2@ua.edu] 
Sent: Thursday, January 22, 2015 10:07 AM
To: Duff Johnson; w3c-wai-ig@w3.org
Subject: PDF accessibility guidelines. WAS: Re: PDF's and Signatures

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 http://accessibility.ua.edu

-----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 15:49:06 UTC

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