PDF/UA defines PDF accessibility requirements
PDF/UA is the ISO standard for accessible PDF. It defines requirements for structure, semantics, text, metadata, and other PDF features that support access with assistive technology. Choose the version appropriate to your PDF format and the requirements of the project.
PDF/UA-1: the PDF 1.7 standard
PDF/UA-1 (ISO 14289-1) addresses PDF 1.7. Review meaningful content tags, heading and list structure, table relationships, text alternatives, logical sequence, character mapping, and document metadata. Automated validation and appropriate human review work together.
PDF/UA-1 is widely used for PDF-specific testing. Section 508 references it for PDF export by authoring tools; covered PDF content itself is assessed against WCAG 2.0 A and AA. See the distinction.
PDF/UA-2: accessibility for PDF 2.0
PDF/UA-2 (ISO 14289-2:2024) specifies accessibility requirements for PDF 2.0. It addresses PDF 2.0 structure types, namespaces, annotations, mathematical content, and other features. Confirm that the tools receiving and testing the file support the target format.
Reports should identify which profile was used and which checks apply to the output. A list of supported profiles is not a claim that one file conforms to every profile.
WTPDF: a free specification for accessibility and reuse
Well-Tagged PDF defines requirements for PDF 2.0 with conformance levels for accessibility and reuse. Its accessibility conformance level is fully compatible with PDF/UA-2: a file conforming to that level also conforms to PDF/UA-2.
WTPDF is available free from the PDF Association. It is more than a tagging-only subset: select the conformance level that matches your use case.
The Matterhorn Protocol 1.1
The protocol describes 31 checkpoints containing 136 failure conditions for PDF/UA-1:
- 87 can be determined by software alone.
- 47 usually require human judgment.
- 2 have no specific tests.
Conditions can apply to a document, a page, or individual objects. Repeated checks across content can produce many test results from one rule. ADAComply runs at least 3,000 validation checks on every PDF, and significantly more when needed. Review the report’s scope alongside the result.
PDF/UA and WCAG are complementary
PDF/UA provides PDF-specific requirements. WCAG defines accessibility outcomes. In most cases, PDF/UA provides a strong foundation for PDF accessibility work, but the applicable WCAG criteria and actual reading experience still need assessment. Read the WCAG guide.
Choose a target before processing
Confirm the required WCAG version, PDF format, accepted validation profile, and human review scope. Use PDF/UA-1 for a PDF 1.7 workflow or PDF/UA-2 and WTPDF accessibility requirements for an appropriate PDF 2.0 workflow.
Questions before you start
What does an automated pass tell me?
It tells you that the automated checks represented in that report passed. Review the profile, coverage, and judgment-based requirements before claiming full conformance.
Where can I read WTPDF and Matterhorn?
Both are available free from the PDF Association using the links below. PDF/UA is published by ISO.