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
Interview with Dietrich von Seggern for PDF Days Europe 2017

Who: Dietrich von Seggern Company: callas software GmbH Position: Managing Director PDF Association: The PDF Days Europe will be held in Berlin again. Do you have any personal relationship with Berlin? Dietrich von Seggern: Yes, definitely. I first cam …

Interop workshops: building a test matrix

How will the PDF 2.0 interop workshops work? This article explains the process of building the test-matrix to establish possibilities for pair-wise testing.

PDF Days Europe agenda looks to the future

Berlin. Those interested in the PDF format can now register for this year’s PDF Days Europe in Berlin. A comprehensive agenda awaits, with over 35 contributions on 15 and 16 May covering all aspects of PDF technology. The focus will be on the PDF Assoc …

SHA-1 is gone… and it’s deprecated in PDF 2.0 as well

As we reported yesterday, those in the crypto world are well-aware that Google and others have proven that SHA-1, the venerable cryptographic hash function standard, is dead. The consequences, however, are yet to be determined. Somewhere, it is safe to …

PDF Days Europe 2017 – Secure your ticket now!

With over 35 informative sessions across a wide range of topics, including the dramatic new “Camelot2” project, this year’s PDF Days event is especially relevant as we look forward into the future of PDF technology.

The Value of Tagged PDF


PDF was originally intended to serve as electronic paper; a properly rendered page irrespective of software or operating system.  Pages, however, aren’t just for reading. Since people like to add notes, draw lines and fill forms, Adobe Systems, the inventors of PDF, decided to cater to these uses as well. PDF rapidly accumulated new features beyond faithfulness to the rendered page – it began to mirror the interactive capabilities of real paper.

The first generation of interactive PDF features consisted of annotations of various types. Some allowed users to add text, others allowed users to draw lines and boxes onto the page. Still others go beyond the paradigm of the page, making it possible to add hyperlinks,  audio and movies to PDF.

The second generation of interactive PDF brought the ability to deploy a PDF’s content outside the page-based world.

Tagged PDF provides the means to effectively deploy a final-form document to a mobile device. It’s the same means by which PDF files may be made accessible to users who requires Assistive Technology (AT) to read.

One of the primary motivations for tagged PDF was to achieve compliance with regulations that require electronic documents to be accessible to users with disabilities, but implementers can leverage tagged PDF to accomplish or enhance a wide range of end user activities.

The following table indicates the utlity of untagged vs. tagged PDF content.

Untagged Content Tagged Content
No semantic types or ordering; content is ordered solely for rendering purposes Semantic type and order is determined, content may be reused accordingly
Search engines cannot reliably access words and phrases Search engines get reliable access to content.
No reliable means of reflowing page content onto smaller devices Includes information necessary for reflow
“Real” content and “artifacts” aren’t distinguished Consuming software can choose to utilize or ignore artifacts
Content copying and extraction is unreliable Content may be extracted with confidence
Not eligible for PDF/A conformance level A May conform with PDF/A conformance level A
Cannot comply with WCAG 2.0 or Section 508 May comply with WCAG 2.0, Section 508 and other accessibility regulations
Inaccessible to disabled users Accessible to those with PDF-aware Assistive Technology

Tags: Section 508, WCAG 2.0, assistive technology, mobile, tags
Categories: PDF, PDF/UA