About the contributor
Duff Johnson

A veteran of the electronic document space, Duff Johnson is an independent consultant. He is Executive Director of the PDF Association and ISO Project co-Leader (and US TAG chair) for ISO 32000 and ISO 14289.
More contributions
What is a “Competence Center”?

The PDF Association started in 2006 as the “PDF/A Competence Center”. The mission was to identify – and thereby establish – a common interpretation of the PDF/A-1 specification. With that accomplished through meetings open to all members, the secondary …

“PDF can do THAT?!”

PDF files deliver a complete package of information that defines a document; everything that’s needed to represent the text, graphics and layout that the recipient receives. To most people, PDF is “electronic paper” – the digital expression of a cellul …

The only digital document format

What is a “document”? A document is a record of some (typically written) content – a publication, a contract, a statement, a painting – at a moment in time. Until the advent of computers (and scanners), the media typically considered useable for such r …

Save the Date: PDF Days Europe 2018, May 14-16, in Berlin

PDF Days Europe is the most popular PDF event of the year. It’s where the PDF industry meets, and where institutional and corporate users come to learn what else PDF could do for them. The first two PDF Days will offer a broad range of educational sessions focussed on current and perennial topics in the world of PDF technology implementation.

The Power of the Page

It’s a question that vexes vendors of web-based solutions everywhere: why do people still insist on PDF files? And why does PDF’s mindshare keep going up? “PDF is such antediluvian technology!” they say. “It’s pre-web, are you kidding me? It’s so old-f …

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