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Re: PDF's and Signatures

From: Duff Johnson <duff@duff-johnson.com>
Date: Thu, 22 Jan 2015 09:47:28 -0500
Message-Id: <983DDC7B-D976-451F-ACBC-4A11713F5588@duff-johnson.com>
To: "w3c-wai-ig@w3.org" <w3c-wai-ig@w3.org>
> I have to disagree slightly with Andy’s 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 what’s 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 (it’s 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=”[Signature: Mickey Mouse]”)

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 Adobe’s tools are as accessible as the rest of Adobe Acrobat / Reader’s UI. This has *nothing* to do, however, with an “ink” 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 14:47:58 UTC

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