How to Optimize PDFs for Accessibility: A Direct Guide

Optimizing a PDF for accessibility isn't just a technical checklist; it's a commitment to ensuring that everyone, especially those relying on assistive technologies like screen readers, can fully engage with your content. Dealing with common PDF accessibility barriers requires a disciplined approach, starting at the source file and continuing through careful remediation. 

This guide outlines the essential steps for creating and fixing accessible PDFs, adhering to standards like WCAG and Section 508.

3 Simple Steps to Optimize PDFs for Accessibility

Step 1: Accessibility Starts at the Source

The foundation for an accessible PDF is always an accessible source document (e.g., Microsoft Word, Adobe InDesign). Trying to fix a fundamentally flawed PDF later will only lead to expensive PDF remediation services.

1. Use Styles for Semantic Structure

Screen readers navigate a document by its structure, not its appearance. This means relying on native features:

• Headings: Use built-in heading styles (Heading 1, Heading 2, etc.) to create a logical, hierarchical map of your content. H1 must be the document title. Never substitute bold text or enlarged fonts for true heading styles.

• Lists: Employ the native bulleted or numbered list functions.

• Tables: Define the Header Row clearly in the source application.

2. Provide Alternative Text for Visuals

• Every non-decorative image like charts, graphs, photos must have descriptive Alternative Text (Alt Text) that conveys its purpose.

• Decorative images (e.g., purely illustrative icons, borders) should be marked as decorative so they are tagged as artifacts in the PDF and ignored by assistive technology.

3. Ensure Link and Contrast Standards

• Links: The anchor text should be descriptive and meaningful.

• Contrast: Ensure sufficient color contrast between text and background. The minimum requirement is typically 4.5:1 for standard text size, crucial for users with low vision.

Step 2: Conversion and Verification

After the source document is flawless, convert it to PDF using the application's "Export" or "Save As Adobe PDF" function never use the "Print to PDF" command, which strips away structural tags.

1. Define Document Properties

In the PDF software, set the document's basic metadata:

• Title: Assign a meaningful, descriptive title that appears in the window bar.

• Language: Set the document’s primary language.

2. Text Selection and OCR

• The PDF must contain actual, selectable text. If the PDF was created from a scanned image, run Optical Character Recognition (OCR) to convert the text image into machine-readable characters.

Step 3: PDF Remediation and Tagging

This is where the heavy lifting of fixing remaining PDF accessibility barriers occurs. While some organizations hire PDF remediation services for this complex task, it is also manageable with the right tools. For a comprehensive overview of the standards this remediation meets, review this helpful PDF remediation guide covering WCAG, Section 508, and EAA.

1. Run the Accessibility Check

• Use the Full Check tool in Acrobat Pro's Accessibility panel. This report flags issues like missing tags, missing Alt Text, and reading order problems.

2. Verify and Correct Tags Tree

The Tags panel is the core of PDF accessibility. It must mirror the logical reading order:

• Content in Tags: Every piece of meaningful content (text, tables, lists) must be enclosed in a tag. Content outside the tag structure is inaccessible.

• Correct Tag Types: Ensure tags reflect the source structure—a heading must be an $\langle H \rangle$ tag, not a $\langle P \rangle$ (paragraph) tag.

• Artifacts: Mark decorative elements as Artifacts to instruct the screen reader to skip them entirely.

3. Define the Logical Reading Order

• The Reading Order is the sequence in which the screen reader moves through content. It must align with the visual flow (e.g., column 1, then column 2). Use the Reading Order tool to inspect and manually adjust the order in the Tags tree as needed.

4. Address Complex Data and Tables

• Use the Table Editor to designate and assign proper table structure tags:

  • Table Headers ($\langle TH \rangle$): Must be correctly assigned to the header cells.

  • Data Cells ($\langle TD \rangle$): Must be correctly assigned to the data cells and be associated with their respective headers.

5. Final Checks

• Check Permissions: Ensure security settings do not restrict "Extract content for accessibility," as this prevents screen readers from accessing the text.

• Test with a Screen Reader: The final validation is testing with a real screen reader (e.g., NVDA, VoiceOver) to confirm that the navigation, tags, and structure are interpreted correctly by the technology users rely on.

Conclusion

By moving beyond simple compliance and focusing on a genuine user experience, you can transform a typical document into a truly optimized and accessible PDF.

Author Bio:

Briana Collins is part of the Content Marketing team at DocumentA11y, a leading pdf remediation and document accessibility service provider's focused on helping organizations make their digital documents accessible and compliant with global standards like WCAG and Section 508. She creates solution driven content that connects with professionals seeking ways to improve document accessibility.