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Document Accessibility

Making PDFs Accessible

By Moss · 10 min read · March 2026

PDF documents are one of the most common sources of accessibility barriers. Unlike web pages, PDFs don't automatically inherit accessibility features from their structure. An accessible PDF requires intentional tagging, reading order, and metadata -- whether created from scratch or remediated after the fact.

Why PDF Accessibility Matters

PDFs are used everywhere -- government forms, financial documents, educational materials, legal notices. When these documents are inaccessible, people who use screen readers, magnification software, or other assistive technologies cannot access critical information.

Under the ADA, Section 508, and the ADA Title II web rule, PDF documents published on websites must be accessible. The relevant standard is PDF/UA (ISO 14289-1), which aligns with WCAG 2.1 AA requirements.

The Foundation: Tagged PDFs

The most important concept in PDF accessibility is tagging. Tags provide the structural information that assistive technologies need to interpret the document.

What Are PDF Tags?

PDF tags are a hidden layer of structural markup, similar to HTML elements. They define:

  • Headings (<H1> through <H6>) -- Document structure hierarchy
  • Paragraphs (<P>) -- Body text
  • Lists (<L>, <LI>, <Lbl>, <LBody>) -- Ordered and unordered lists
  • Tables (<Table>, <TR>, <TH>, <TD>) -- Data tables with headers
  • Figures (<Figure>) -- Images and graphics with alt text
  • Links (<Link>) -- Hyperlinks
  • Forms (<Form>) -- Interactive form fields

Untagged vs. Tagged PDFs

An untagged PDF is essentially a flat image of text. Screen readers may attempt to extract text, but without tags they cannot communicate structure, headings, lists, or table relationships. The reading order may be incorrect, and images will have no alternative text.

A tagged PDF provides the complete structural information needed for assistive technology to present the document accurately.

Creating Accessible PDFs

From Microsoft Word

  1. Use built-in styles: Apply Heading 1, Heading 2, etc. from the Styles pane. Don't manually format text to look like headings.
  2. Add alt text to images: Right-click the image, select "Edit Alt Text," and write a concise description.
  3. Use proper lists: Use Word's bulleted or numbered list tools rather than manually typing dashes or numbers.
  4. Create real tables: Use Word's table insertion tool. Include header rows and avoid merged cells when possible.
  5. Set the document language: File > Options > Language.
  6. Export correctly: Use "Save As PDF" or "Export to PDF" rather than printing to PDF. Ensure "Document structure tags for accessibility" is checked.

From Adobe InDesign

  1. Map paragraph styles to tags: Use the Tags panel to map each paragraph style to the appropriate PDF tag.
  2. Set reading order: Use the Articles panel to define the reading order of content.
  3. Add alt text: Use Object > Object Export Options to add alt text to images.
  4. Export with tags: In the Export to PDF dialog, check "Create Tagged PDF."

From Google Docs

Google Docs can export accessible PDFs if you use built-in headings, lists, and add alt text to images. However, the exported PDFs often require additional remediation for full compliance.

Remediating Existing PDFs

Many organizations have large libraries of existing PDFs that need remediation. Adobe Acrobat Pro is the primary tool for this work.

Key Remediation Steps

  1. Run the accessibility checker: Acrobat's built-in checker identifies common issues.

  2. Add tags: If the PDF is untagged, use "Autotag Document" as a starting point, then manually review and correct the tag structure.

  3. Fix reading order: Use the Reading Order tool or the Tags panel to ensure content is read in the correct sequence. Multi-column layouts often have incorrect reading order.

  4. Add alt text to images: Select each <Figure> tag and add appropriate alternative text. Mark decorative images as artifacts.

  5. Fix tables: Ensure tables have proper header cells (<TH>) and that the scope (row or column) is set correctly. Complex tables with merged cells may need manual tag editing.

  6. Set document properties: Add a document title (displayed in the title bar instead of the filename), set the language, and ensure "Display Document Title" is selected in Initial View settings.

  7. Make forms accessible: Each form field needs a label, a tooltip, and proper tab order.

PDF Accessibility Checklist

Use this checklist to verify your PDF meets accessibility requirements:

Document Structure

  • Document has tags
  • Tags accurately represent the document structure
  • Reading order is correct
  • Headings follow a logical hierarchy (H1 > H2 > H3)
  • Document language is set
  • Document title is set and displayed

Images

  • All informative images have alt text
  • Decorative images are marked as artifacts
  • Complex images have detailed descriptions
  • Alt text is concise and describes the content or function

Tables

  • Tables have header rows or columns
  • Header cells use <TH> tags
  • Data cells use <TD> tags
  • Tables do not use merged cells unnecessarily
  • Layout tables are not tagged as data tables

Links

  • Links have descriptive text
  • Links are tagged as <Link> elements
  • URLs are not used as the only link text

Forms

  • Form fields have labels
  • Form fields have tooltips
  • Tab order is logical
  • Required fields are identified
  • Error messages are associated with fields

Text

  • Text is real text (not images of text)
  • Text can be selected and copied
  • Font size is adequate (minimum 12pt recommended)
  • Color is not the sole means of conveying information

Testing PDF Accessibility

Automated Testing

  • Adobe Acrobat Pro Accessibility Checker: Built-in tool that checks for common issues.
  • PAC 2024 (PDF Accessibility Checker): Free tool from the PDF/UA Foundation that tests against PDF/UA standards.

Manual Testing

  • Screen reader testing: Read the entire document with NVDA, JAWS, or VoiceOver to verify the experience.
  • Reading order verification: Use Acrobat's Reading Order tool to visually verify the sequence.
  • Keyboard navigation: Tab through all form fields and links.

Common Pitfalls

  • Scanned documents: A scanned PDF is just an image. You must run OCR first, then add tags and structure.
  • Flattened forms: Forms that have been "flattened" lose their interactive fields and are no longer fillable or accessible.
  • Watermarks and backgrounds: These can interfere with reading order if not properly marked as artifacts.

Next Steps

PDF accessibility is a deep topic. For organizations with large document libraries, consider:

  • Prioritizing high-traffic documents for remediation first
  • Training content creators to produce accessible source documents
  • Using Adaline to audit and track document accessibility compliance across your organization
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