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About the contributor
Duff Johnson

A veteran of the electronic document space, Duff Johnson is an independent consultant, Executive Director of the PDF Association and ISO Project co-Leader (and US TAG chair) for ISO 32000 and ISO 14289.
More contributions
Save-The-Date: PDF Day France, Toulouse, April 4, 2019

PDF Day France will be the first French-speaking event of the PDF Association, organised by our member ORPALIS. It will take place in Toulouse which is the home ground of Airbus and we are very happy that Airbus will present a case study around its usage of PDF in their document management environment!

Electronic Document Conference: Call for Papers

Prospective presenters at the Electronic Document Conference 2019 are invited to submit high-quality original proposals for 25-minute presentations on subjects of interest to developers and technical product managers concerned with electronic document implementations.

Have we passed ‘peak PDF’?

How do we gain insight into how users’ views of documents are shifting? Google Trends is an increasingly interesting source of high-level marketplace data. By aggregating Google’s search data over time, reporting a term’s popularity as compared with all other searches.

Participating in the PDF Techniques Accessibility Summit

The PDF Techniques Accessibility Summit’s objective is to establish a broad-based understanding of how PDF files should be tagged for accessibilty. It’s an opportunity to focus on establishing a common set of examples of accessible PDF content, and identify best-practice when tagging difficult cases.

Members supporting PDF features!

The typical adoption curve for PDF technologies until approximately 2007 tended to track with that of the original PDF developer. Since then the marketplace has shifted; it’s no longer clear that Adobe drivesPDF feature support worldwide. Accordingly, we are happy to report that adoption of PDF 2.0 continues apace, with new vendors announcing their support every month.

The Case for PDF/UA

PDF/UA icon.Among the greatest contributions of WCAG 2.0 to the cause of improving electronic content accessibility are 4 Principles and 12 Guidelines. These concepts underlie WCAG 2.0’s Success Criteria; they are timeless statements that will shape the technical discussions about implementing accessibility in electronic content for decades to come.

WCAG 2.0’s Success Criteria (61 in all) are most easily understood and directly applied to HTML/CSS/JavaScript and other technologies that were created for the World Wide Web.

Applying WCAG 2.0’s Success Criteria to non-web technologies offers some challenges, a fact that’s readily apparent when one considers the case of PDF. As Adobe Systems put it in their recent blog post:

“PDF/UA defines the technical specifications to enable PDF documents to meet WCAG 2.0, but WCAG 2.0 has additional requirements which require an author’s attention.”

In a recent series of articles posted on his Logical Structures blog, NetCentric Technologies President and PDF Association Vice Chairman Duff Johnson discusses a seminal question in electronic content accessibility: the correct use of headings. He goes on to use this example to unveil some of the distinctions between WCAG 2.0 and PDF/UA.

In the first article, “Heading Levels: Navigation or Decoration” Johnson exposes the distinctions between the definitions of “heading” in HTML and PDF. After discussing how we collectively arrived at this point, he argues that PDF/UA’s requirement for valid heading structures is appropriate in PDF because many PDF use-cases cause assistive technology users to depend on document structure for navigation.

In his second article in the series, “Defining Heading in HTML and PDF”, Johnson reviews in detail the technical definitions of headings in HTML and PDF in order to understand their role in WCAG 2.0. He goes on to suggest that Success Criterion 1.3.1 should be read as normatively requiring correct heading structures, at least in the use-cases (longer and complex documents) common to PDF.

Johnson’s third article asks, “What follows WCAG 2.0?” He points out that while WCAG 2.0 has so far chalked up important regulatory support actual software implementations are lacking. The conclusion makes the point that technology-specific standards are more attractive to implementers while offering more consistent and interoperable results than is likely following WCAG 2.0 alone.

The closing article of this four-part series is an introduction to PDF/UA in non-technical terms. The piece provides five easy-to-understand reasons why PDF/UA matters in terms that make sense to end users.

Read all four articles on Duff Johnson’s Logical Structures blog.


Tags: WCAG 2.0, accessibility, logical structures
Categories: PDF/UA