Accessible PDFs ensure everyone can access your content, including people using screen readers or other assistive technologies. Here's how to create inclusive documents.
Why PDF Accessibility Matters
Legal Requirements
Many organizations must provide accessible documents:
- Section 508 - US federal agencies
- ADA - Businesses serving the public
- WCAG 2.1 - Web content guidelines
- EU Accessibility Act - European requirements
Reaching Everyone
Accessibility benefits:
- Blind and low-vision users
- Users with cognitive disabilities
- Motor impairment (keyboard navigation)
- Temporary disabilities
- Mobile and situational limitations
Better for All
Accessible documents are:
- Better structured
- Easier to navigate
- More searchable
- Future-proof
What Makes a PDF Accessible?
Tagged Structure
Tags define document structure:
- Headings (H1, H2, H3)
- Paragraphs
- Lists
- Tables
- Figures
Screen readers use tags to navigate and understand content.
Reading Order
Defines the sequence content is read:
- Logical flow through document
- Multi-column layouts read correctly
- Sidebars handled appropriately
Alternative Text
Descriptions for non-text content:
- Images
- Charts and graphs
- Decorative vs informative elements
Color and Contrast
Visual accessibility:
- Sufficient contrast ratios
- Information not conveyed by color alone
- Readable fonts
Forms and Links
Interactive elements:
- Labeled form fields
- Descriptive link text
- Keyboard accessible
Creating Accessible PDFs
Start with Accessible Source
Best approach: Create accessibility at the source.
From Word:
1. Use Heading styles (don't just make text big/bold)
2. Add alt text to images
3. Use built-in list formatting
4. Create proper table headers
5. Export to PDF with tags
From InDesign:
1. Use paragraph styles
2. Set reading order
3. Tag content properly
4. Export as accessible PDF
Fixing Existing PDFs
If you have an inaccessible PDF:
1. Add tags
2. Set reading order
3. Add alt text
4. Fix form labels
5. Verify accessibility
Tools: Adobe Acrobat Pro, CommonLook, axesPDF
Key Accessibility Features
Document Title
Set a meaningful title:
- File > Properties > Title
- Appears in browser tabs
- Announced by screen readers
Language Setting
Define document language:
- File > Properties > Language
- Enables correct pronunciation
- Required for screen readers
Headings Hierarchy
Use proper heading levels:
- H1: Main title (one per document)
- H2: Major sections
- H3: Subsections
- Don't skip levels
Table Structure
Accessible tables need:
- Header row/column defined
- Scope for headers
- Caption/summary
- Simple structure (avoid merged cells)
Lists
Use proper list formatting:
- Bulleted lists tagged as lists
- Numbered lists tagged correctly
- Screen readers announce "list of 5 items"
Images
For every image, decide:
- Informative: Add alt text describing content
- Decorative: Mark as artifact (ignored by screen readers)
Alt text tips:
- Describe the information conveyed
- Be concise but complete
- Don't start with "Image of..."
Links
Link accessibility:
- Use descriptive text ("Download annual report")
- Avoid "click here" or bare URLs
- Indicate if link opens new window/file type
Forms
Accessible form fields:
- Every field has a label
- Labels are associated with fields
- Instructions are clear
- Error messages are descriptive
- Tab order is logical
Testing Accessibility
Automated Checks
Use accessibility checker tools:
Adobe Acrobat:
1. Tools > Accessibility > Accessibility Check
2. Run full check
3. Review and fix issues
Free Tools:
- PAC 3 (PDF Accessibility Checker)
- PAVE (PDF Accessibility Validation Engine)
Manual Testing
Automated tools can't catch everything:
Screen Reader Testing:
1. Use NVDA (free) or JAWS
2. Navigate the document
3. Can you access all content?
4. Does reading order make sense?
Keyboard Testing:
1. Tab through the document
2. Can you reach all interactive elements?
3. Is focus visible?
4. Does order make sense?
Color Contrast Check
Use contrast checking tools:
- WebAIM Contrast Checker
- Colour Contrast Analyser
- Built-in browser tools
Minimum ratios:
- 4.5:1 for normal text
- 3:1 for large text
Common Accessibility Issues
Problem: No Tags
Symptom: Screen reader reads text in wrong order or says "no content."
Fix: Add tags using Acrobat or accessibility tool.
Problem: Images Without Alt Text
Symptom: Screen reader says "graphic" with no description.
Fix: Add alt text via Tools > Accessibility > Set Alternate Text.
Problem: Incorrect Reading Order
Symptom: Content read in confusing sequence.
Fix: Adjust reading order in Tags panel or Order panel.
Problem: Scanned PDF (Image Only)
Symptom: Entire document is one image, no selectable text.
Fix: Run OCR to create searchable/tagged content.
Problem: Color-Coded Information
Symptom: Charts or instructions rely only on color.
Fix: Add patterns, labels, or other non-color indicators.
PDF/UA Standard
PDF/UA (Universal Accessibility) is the ISO standard:
Requirements Include:
- All content is tagged
- Tags reflect logical structure
- Alternative text for images
- Proper reading order
- Document title and language set
Checking PDF/UA Compliance
Use validators like:
- PAC 3
- Adobe Preflight
- Common Look
Quick Accessibility Checklist
Document Level
- [ ] Title is set
- [ ] Language is defined
- [ ] Document is tagged
Content
- [ ] Headings use proper hierarchy
- [ ] Images have alt text
- [ ] Lists are tagged as lists
- [ ] Tables have headers
Navigation
- [ ] Reading order is logical
- [ ] Links are descriptive
- [ ] Bookmarks for long documents
Visual
- [ ] Sufficient color contrast
- [ ] Information not color-only
- [ ] Text is resizable
Forms (if applicable)
- [ ] Fields are labeled
- [ ] Tab order is logical
- [ ] Instructions are clear
Making Existing Documents Accessible
Quick Fixes
For documents that need basic accessibility:
1. Add title and language
2. Auto-tag the document
3. Run accessibility check
4. Fix critical issues
Full Remediation
For complete accessibility:
1. Analyze document structure
2. Rebuild tag tree properly
3. Add all alt text
4. Set correct reading order
5. Test with assistive technology
When to Recreate
Sometimes it's easier to:
- Go back to source document
- Create properly from scratch
- Use accessible template
Conclusion
PDF accessibility benefits everyone:
- Start accessible - Use structured source documents
- Tag properly - Headings, lists, tables, images
- Test thoroughly - Automated and manual testing
- Fix issues - Address problems found
Need to make your PDF accessible? Start with LexoSign's PDF tools to ensure your documents work for everyone.
Accessibility isn't just compliance - it's ensuring your content reaches everyone who needs it.