It is tempting to treat an accessibility checker like a spell checker: run it, fix the red items, publish. Many organisations do exactly that, and many of those documents are still difficult or impossible to use with a screen reader. A checker is an essential first step, but it answers a narrower question than the one that matters.
What automated checkers do well
Tools such as Adobe Acrobat's Accessibility Checker and PAC, the free PDF/UA checker, inspect the technical structure of a file. They reliably detect problems like these:
- The document is not tagged at all.
- The document title or language is missing.
- Images have no alternative text.
- Tables have no header cells.
- Fonts are not embedded or text cannot be extracted.
- Form fields have no name or description.
These are real barriers, and fixing them is mandatory. PAC in particular checks against the PDF/UA standard (ISO 14289) and the machine-testable parts of WCAG, which makes it the reference tool for remediation work.
What they cannot judge
A checker can confirm that alternative text exists; it cannot tell whether it says anything useful. It can confirm that a heading is tagged; it cannot tell whether it is the right heading. The most common problems in documents that pass every automated test are these:
- Wrong reading order. Columns, sidebars and captions read in the wrong sequence, so the text makes no sense.
- Meaningless alt text. “image1.jpg” or “chart” instead of what the chart actually shows.
- Broken heading structure. Levels skipped or used for visual size rather than hierarchy.
- Decorative elements read aloud. Lines, background shapes and repeated logos announced on every page.
- Tables that only look right. Headers tagged, but merged cells associated with the wrong data.
- Unclear links. Ten links called “click here”, impossible to tell apart.
What a complete review looks like
Good remediation combines three passes. First, the structural work: tags, reading order, alternative text, tables, lists, links, form fields and metadata. Second, the automated check with PAC until no errors remain. Third, a manual review: reading the document with a screen reader such as NVDA, checking the reading order panel, and confirming that every image description and table makes sense to someone who cannot see the page.
That third pass is the one most often skipped, and the one that decides whether a person can actually use the document.
Ask for evidence, not a badge
Be cautious with anyone who promises a “certified accessible” PDF from an automated report alone. Ask instead for a report per document: what was fixed, the PAC result and notes from the screen reader test. That is what we deliver with every batch in our PDF accessibility remediation service, from $390 for up to 50 pages.
Preparing a batch? Read how to prepare PDFs for remediation.