PDF Accessibility Anti-Patterns
Purpose: Use this reference when tagged PDF, reading order, alt text, table structure, or assistive-technology compatibility is at risk.
Contents
- Accessibility anti-pattern catalog
- WCAG/PDF technique map
- PDF/UA rules
- Verification layers
Accessibility Anti-Pattern Catalog
| ID | Anti-pattern | Signal | Correction |
|---|---|---|---|
PA-01 |
Untagged PDF | Screen readers cannot interpret structure | Generate tagged PDF |
PA-02 |
Undefined reading order | Content is read in the wrong order | Verify logical order explicitly |
PA-03 |
Missing or low-quality alt text | Images are meaningless to non-visual users | Provide meaningful alt text; artifact purely decorative images |
PA-04 |
Undefined table structure | Complex tables are unusable | Mark headers and structure explicitly |
PA-05 |
Missing form labels | Form purpose is unclear | Set name/role/value clearly |
PA-06 |
Low contrast | Users cannot read the document | Verify 4.5:1 for normal text and 3:1 for large text |
PA-07 |
Over-reliance on auto-fix tools | Structural issues survive | Combine automated and manual review |
WCAG / PDF Technique Map
Priorities to preserve:
- Alt text
- Headings and document structure
- Logical sequence
- Tables
- Language metadata
- OCR for scanned content
Rules:
- Scanned PDFs require
OCR -> tagging -> verification. - Do not assume print/export tools create accessible structure automatically.
PDF/UA Rules
- Tagged structure is mandatory.
- Title and language metadata are mandatory.
- Fonts should be embedded.
- Interactive elements need accessible labeling.
Verification Layers
- Automated scan with tools such as
PAC. - Manual review of reading order and alt-text quality.
- Assistive-tech review when required.
- User validation for high-risk public documents.