What is a PDF?
PDF stands for Portable Document Format. The original intention with PDFs, when the file format was created by Adobe in 1991, was to share documents with other users that may not have the same software as you. At that time, for example, not everyone had access to Microsoft suites. 1991 was two years before the World Wide Web would become public and it would take quite a while for the Internet to mature into the digital universe we are used to today.
Today, printing PDFs is far less common, and many users use mobile devices as much if not more often as desktop computers to communicate. In that regard, PDFs are no longer always the ideal format for publishing content. The best reason to use PDFs is still to be able to print hand copies of content, which in and of itself is not very accessible. In 2020, the Nielsen Norman Group published an article called PDF: Still Unfit for Human Consumption, 20 Years Later, which covers the various issues with PDFs.
What is PDF accessibility?
PDF accessibility ensures that disabled people accessing your PDF with assistive technology can access and navigate the content in an equally effective way to anyone not using assistive technology. PDF accessibility focuses on the behind-the-scenes structure of the file. When you access the inner workings, you will find that the code looks very similar to the code on a website with <p> tags for paragraphs, <h2> tags for the main sections of a PDF, <image> for image, etc. This structure can be delivered well if a person is making their source file accessible. For example, a simple Word document converted to a PDF that has already been designed with accessibility in mind will most likely pass all accessibility checks as the correct structure is behind the scenes. However, documents that were not built with accessibility in mind will need significant remediation on the PDF side.
PDF accessibility itself is tricky though. Complex content such as interactive forms and maps may be impossible to make accessible. Even when one has checked all the boxes from a compliance standpoint, the PDF still may not be usable by assistive technology users. For example, PDFs do not support high contrast mode or dark mode, which means employees with light sensitivity or low vision that require these display modes will not have an equally effective experience. In addition, no matter how much time you spend on trying to remediate complex PDFs, the experience may not be usable for screen reader users.
We recommend reviewing the Before You Get Started and PDF Usage Guidelines sections of this guide to ask yourself whether remediating your PDF is the best option.