PDF Techniques for Accessibility

Accessible PDF illustration

PDF Association introduces a new model​

In 2018, the PDF Association’s PDF Accessibility Liaison Working Group launched a project to develop a definitive set of techniques for accessibility in PDF files.

The PDF Association is about to publish its first set of “Fundamental Techniques.” To give a preview of what is coming, we are already presenting examples of PASS and FAIL techniques.

In this short article, you will learn how these techniques improve on parts of the existing WCAG approach.

Comprehensive​

When WCAG 2.0 was published in 2008, it initially included 23 techniques for PDF. Although there have been minor updates since then, the scope and format have remained largely unchanged. There are no PDF examples, and the application screenshots are (naturally) vendor-specific. In general, the PDF information on w3.org has been outdated since 2008.

Although we are currently publishing only one PASS and one corresponding FAIL method to illustrate the model, the next release, announced for before the end of 2023, will include 36 “Fundamental” methods that apply to all PDF files.

Beyond the fundamentals, the team planned to publish “Use Case” techniques starting in early 2024, covering the many types of content that can appear in PDF. So far, the Accessibility LWG has developed more than 160 of these “Use Case” techniques and expects many more to follow.

Example-based information​

The PDF Association’s techniques do not provide instructions for specific software. Instead, they include “atomic” PDF examples, each representing a minimal case of a technique so the focus remains on the key information in every case.

Vendor-neutral​

A key criticism of the original WCAG techniques for PDF is that they rely on instructions for specific (and now outdated) software packages instead of focusing on correct and incorrect outcomes in the PDF file itself.

The new PDF Association techniques are fully vendor-neutral and describe outcomes rather than applications or specific workflows. This approach was chosen to ensure that all vendors and users have the same opportunity to understand and apply these techniques in their own context.

Test procedures aligned with WCAG​

To ensure compatibility with WCAG, the PDF Accessibility LWG adopted a similar approach for describing techniques and their corresponding tests.

The “Technique Finder”​

Each technique is published on its own page at pdfa.org. In addition, the PDF Association introduced the “Technique Finder,” a string that uniquely identifies each technique for search engines.

The purpose of the “Technique Finder” is to help users quickly determine whether a specific vendor or software package supports a specific technique. Users can simply search for the vendor name plus a given “Technique Finder” code to find pages documenting that vendor’s approach to the technique.

Glossary​

In addition to the techniques themselves, the PDF Accessibility LWG has created a glossary of key terms used in both the fundamental techniques and the use-case techniques.

Target audience​

The PDF Association’s accessibility techniques are intended as guidance for two main groups:

  • End users can use these techniques to learn how to tag or review PDF files.
  • Developers can use these techniques to understand the technical requirements of accessibility.