PAC 2021 - The Free PDF Accessibility Checker
Instantly check for WCAG and PDF/UA
compliance of your PDF files.
What Is PAC?
PAC stands for PDF Accessibility Checker. It was initially released in 2010 and was the first automated PDF/UA compliance validation tool. Having had three previous versions before PAC 2021, PAC is designed to easily identify all of the machine verifiable success criterion of ISO 14289-1 (PDF/UA) and WCAG (Web Content Accessibility Guidelines).
108The number of machine verifiable test criterion within the Matterhorn Protocol
2010The year PAC 1.0 was first released
5Number of languages PAC is already available: Danish, English, French, German, Spanish
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The History of PAC
The History of PAC is closely connected to the history of PDF/UA and the Matterhorn Protocol. Here are some of the most important milestones:
08-2021PAC 2021 released
The PDF/UA Foundation is the new home of PAC. The 2021 release includes enhanced features like the WCAG check set, and a new color contrast check.
04-2021Matterhorn Protocol 1.1
The 1.1 release of the Matterhorn Protocol adds a new failure condition and provides several clarifications.
12-2017PAC 3 released
The PAC 3.0 release is available with a German user interface and a printable Summary Report.
Roberto Bianchetti, Markus Riesch and Andreas Uebelbacher present their scientific paper "PDF Accessibility Checker (PAC 2): The First Tool to Test PDF Documents for PDF/UA Compliance“ at the 14th International Conference on Computers Helping People with Special Needs (ICCHP) in Paris (France).
07-2014PAC 2 released
Again a world premiere: The release of PAC 2.0 is the first global tool to test PDF documents for PDF/UA compliance.
08-2013Matterhorn Protocol 1.0
The Matterhorn Protocol 1.0 is published by the PDF Association. It's a list of all the possible ways to fail PDF/UA-1, and simplifies the support of the ISO standard for software developers and service providers.
PDF/UA is published as an ISO standard (ISO 14289-1:2012). UA stands for Universal Accessibility. It defines all essential requirements for accessible PDF documents, PDF software, and assistive technology for creating, checking, and using PDF/UA compliant files.
08-2012PAC 1.3 released
The release of PAC 1.3 introduces a new detailed report. It simplifies locating the issues directly in the document view.
Markus Erle and Samuel Hofer present their scientific paper "Validity and Semantics – Two Essential Parts of a Backbone for an Automated PDF/UA Compliance Check for PDF Documents“ at the 13th International Conference on Computers Helping People with Special Needs (ICCHP) in Linz (Austria).
09-2011PAC is picked up worldwide
PAC is picked up by more organizations and experts around the world. For example, the German UPA (Usability Professionals Association) starts referencing it in their Digital Accessibility Guide.
03-2010PAC 1 Beta released
A world premiere: PAC, the first free PDF accessibility checking tool, becomes available. It contains Syntax Checks and the very useful Screen Reader Preview.