A practical, plain-English checklist for making any PDF accessible and conformant with WCAG 2.1 and PDF/UA — from the team that remediates documents for banking and government clients.
A PDF that looks fine on screen can be completely unusable for someone relying on a screen reader. Accessibility laws like the AODA in Ontario and Section 508 in the US require documents to be accessible, and the technical bar is set by WCAG 2.1 Level AA and PDF/UA (ISO 14289). The checklist below walks through what each compliant PDF needs.
Tags are the invisible structure that tells assistive technology what each element is — a heading, a paragraph, a list, a table. An untagged PDF has no structure and is the single most common accessibility failure. Every accessible PDF must be a tagged PDF.
The order in which a screen reader announces content must match the intended visual order. Multi-column layouts, sidebars, and callouts often need the reading order corrected so the document makes sense when read aloud.
Headings must be tagged as actual heading levels (H1, H2, H3…) in a logical hierarchy — not just text made large and bold. Headings let users navigate and understand the document's structure.
Every image that conveys information needs concise, descriptive alt text. Purely decorative images should be marked as artifacts so screen readers skip them.
Data tables need properly tagged header cells and a clear row/column structure so screen-reader users can understand which header applies to each cell. Layout tables should be avoided or handled carefully.
Bulleted and numbered lists must be tagged as real lists, not paragraphs with manual bullets, so they are announced as lists with the correct number of items.
Links should be tagged and have meaningful text ("Download the 2026 report") rather than bare URLs or "click here," so they make sense out of context.
If the PDF is a form, every field needs a programmatic label and a logical tab order. Where appropriate, required fields and clear error/help information help all users complete the form.
Text must meet WCAG contrast ratios (generally 4.5:1 for normal text). Note: a specialist verifies contrast but does not change brand colours unilaterally — colour choices are the document owner's decision to approve.
Information conveyed by colour (for example "fields in red are required") must also be conveyed another way, such as with text or an icon.
The PDF needs a meaningful document title in its properties (and set to display in the title bar) and a specified language so screen readers use the correct pronunciation.
For longer documents, bookmarks provide a navigable outline. Complete document metadata (title, author, subject) supports both accessibility and discoverability.
Run an automated check (Adobe's Accessibility Check or the free PAC tool against PDF/UA), but never stop there. Automated tools catch only part of the picture — reading order, meaningful alt text, and correct heading structure all require manual review by a person who tests with a screen reader. The Matterhorn Protocol provides a detailed checkpoint list for confirming PDF/UA conformance.
Scanned documents need an extra first step: run OCR to turn the image of text into real, selectable text before tagging and remediation begin.