What is PDF/UA? Accessible PDFs explained, and how to check one

What makes a PDF accessible

A screen reader does not see the page; it reads the structure behind it. PDF/UA asks for that structure to exist and be correct.

• Tags: every heading, paragraph, list and table is marked as what it is, in reading order.
• A declared language, so the text is pronounced correctly.
• A document title that readers show instead of the file name.
• Alternative text for images that carry meaning; decorative images marked as such.
• Real, selectable text — a scan must be OCR-ed first.

What a check can and cannot tell you

Some rules can be checked by software: is the file tagged, is the language set, do images have alternative text at all. Others need a person: is the alternative text actually a good description, is the reading order the one a reader expects, does a table make sense read cell by cell. An honest check reports both — what passed, what failed, and what it cannot judge.

Check a PDF

Check PDF accessibility tests a file against the machine-checkable parts of PDF/UA and gives you a written report that also lists what still needs a human look.

Fix the common gaps

Fix PDF accessibility adds the structure tags (headings, paragraphs, lists), declares the document language, sets the title and turns on the setting that makes readers show it. It is a strong start for an untagged document; review the result and describe important images yourself.

1. Run Check PDF accessibility to see what is missing.
2. Run Fix PDF accessibility on the file.
3. Check again, then review images and reading order by hand.

PDF/UA, WCAG and Section 508

WCAG is the general web accessibility guideline; PDF/UA is the PDF-specific standard that puts it into practice for documents. In the United States, Section 508 requires federal agencies to make documents accessible, and PDF/UA is the usual way a PDF shows it. Meeting PDF/UA is strong evidence of accessibility, not a legal certificate.