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PDF/UA – Universal Accessibility Standard
A PDF document is considered accessible if it meets specific requirements contained in the PDF/UA standard (Universal accessibility). PDF/UA is the common name for ISO 14289, an international standard approved in 2012. This standard defines the correct use of PDF tagging for maximum accessibility.
For more information about PDF/UA, check out this great document–PDF/UA in a Nutshell–created by the PDF Association.
Did you know? PDFs are indexed in Google search results and generally rank similarly to other web pages.
The PDF Association also created an extremely useful and detailed document to help software developers and document testers meet PDF/UA conformance. This is their latest version published in 2021:
The Matterhorn Protocol is a set of 31 checkpoints comprised of 136 failure conditions encompassing file format requirements specified in PDF/UA-1.
Did you know? 47 failure conditions require human judgment. This means that PDF document remediation can be very expensive $. The smartest approach is ALWAYS to do as much accessibility work within the source document (i.e., MS Word, InDesign, etc.) prior to exporting to PDF.
Some of the main requirements for a compliant PDF
- All elements must be tagged, and be semantically appropriate.
- All decorative elements must be marked as artefacts
- Appropriate semantic tags must be used with meaningful content
- Logical reading order (order of tags) must be defined
- Only standard tags (as defined in PDF 1.7) may be used. However, if any other tags are used, a role assignment entry must record which standard tag each one represents
- Contrast, colour, or position on the page cannot be used to convey information.
- Content that flickers, blinks, or flashes are not allowed
- A document title is required and must appear in the window title
- The language of the document must be specified and any changes in language must be explicitly marked
- Non-text elements need text alternatives (description)
Did you know? Today, over 70% of PDFs produced on desktop computers are still completely untagged, while those that are tagged are frequently substandard.
Where to start? – Links & Resources
Authoring accessible source documents
- Make your Word documents accessible to people with disabilities (Microsoft)
- Make your PowerPoint presentations accessible to people with disabilities (Microsoft)
- Creating accessible PDFs (Adobe)
- Create and verify PDF accessibility (Acrobat Pro)
Free PDF Accessibility Tools
- PDF Accessibility Checker (PAC) 2021 (very useful & free tool)
- Matterhorn Protocol 1.1 – PDF/UA Conformance Testing Model
- PDF Techniques for WCAG 2.0
- PAVE – Four steps to an accessible PDF
- Online PDF checker (Datalogics)
- PDF/UA Reference Suite 1.1 (documents included in this package demonstrate correct tagging for a number of sophisticated cases)
- Tagged PDF Best Practice Guide: Syntax