PDF/UA: Making PDFs Accessible to Everyone
PDF is widely used because documents look the same on any viewer and are easy to share. But people with disabilities cannot always access PDFs in the way they need. PDF/UA is the standard designed to close that gap.
What Is PDF/UA?
PDF/UA (Portable Document Format/Universal Accessibility) is an ISO-developed standard that defines how to make PDF files accessible to people with disabilities. It was first created with screen reader users in mind, particularly people who are blind or have low vision, and draws heavily on the Web Content Accessibility Guidelines (WCAG).
Its scope is now broader. PDF/UA sets out the features and requirements that make PDFs usable for people with visual, cognitive, and mobility impairments, including those who rely on assistive technologies.
Key Features of PDF/UA
- Document structure: Headings, lists, tables, and other elements must be properly marked up so assistive technologies can interpret the content and present it sensibly. This is covered further in the section on tagging below.
- Alternative text: Images and other non-text elements need text descriptions that convey their meaning to people who cannot see them.
- Color contrast: Text and other elements must be distinguishable for users with visual impairments.
- Reading order and navigation: Content should follow a logical order, with navigation features that assistive technologies can interpret correctly.
- Accessible forms: Interactive forms must be usable and completable with assistive technologies.
- Document language: The document's language should be specified so text-to-speech tools and other language-dependent features work accurately.
- Metadata: Accessibility-related metadata can describe the document's structure and content.
Working with forms in regulated industries? Learn more about PDF form compliance for healthcare, finance, and government.
Tagged PDFs and PDF/UA
Every PDF/UA file is a tagged PDF, meaning it carries semantic and structural information about its visual content. The standard's tagging requirements are intended to ensure that:
- Images have alternative text.
- Tables and lists are tagged as such, rather than appearing as unstructured text.
- Information is never conveyed by visual means alone. For example, a warning shown only in red text would not meet the standard.
The goal is for a screen reader to present a representation of the document that is as complete and useful as the visual version.
Creating PDF/UA Files
PDF/UA files are meant to be produced at creation time by authoring tools. Converting an existing PDF afterward is costly and labor-intensive, and automated conversion is not expected to produce compliant files.
Managing a large document archive? See how to convert PDFs to PDF/A at scale for compliance archiving.
Even so, interest in PDF/UA is growing. Governments are mandating equitable access to online information, and lawsuits and judgments against various organizations have raised the stakes. In the US, updates to Section 508 are expected to require that PDFs posted on government websites meet the PDF/UA standard.
Conclusion
Organizations and individuals who want to publish accessible PDFs should aim for PDF/UA compliance, since it helps ensure documents can be used by a diverse audience. However, PDF/UA is only one part of accessible content. Creators should also follow related standards such as WCAG for a comprehensive approach.