PDF Tools — Acrobat, pa11y-pdf

In this tutorial, you will learn about PDF Tools. We cover key concepts, practical examples, and best practices to help you master this topic.

PDF Accessibility tools range from authoring applications like Adobe Acrobat Pro that create and repair tagged structure, to automated checkers like pa11y-pdf that validate Compliance in CI/CD pipelines, to screen readers like NVDA that provide final user testing.

What You'll Learn

You will learn about the main categories of PDF accessibility tools, how to use Adobe Acrobat Pro for manual remediation, how to integrate pa11y-pdf into automated workflows, and how to choose the right tool for each phase of your accessibility workflow.

Why It Matters

Creating accessible PDFs requires a combination of authoring tools, automated checkers, and manual review. Relying on any single tool misses issues. Understanding the tool landscape ensures you catch problems at every stage.

Real-World Use

A publishing company produces 500 PDF reports per month. Manual checking each one is impossible. They integrate pa11y-pdf into their CI/CD pipeline to automatically flag untagged documents, missing alt text, and poor reading order, reducing manual review from 3 hours to 15 minutes per report.

Tool Categories

flowchart TD
  A[PDF Accessibility Tools] --> B[Authoring Tools]
  A --> C[Automated Checkers]
  A --> D[Manual Review]
  A --> E[Screen Readers]
  B --> F[Adobe Acrobat Pro]
  B --> G[Microsoft Word]
  B --> H[InDesign]
  C --> I[PAC 2021]
  C --> J[pa11y-pdf]
  C --> K[axe-pdf]
  D --> L[Tag Tree Inspection]
  D --> M[Reading Order Tool]
  D --> N[Color Contrast Analyzer]
  E --> O[NVDA]
  E --> P[JAWS]

Adobe Acrobat Pro

The industry standard for PDF remediation. Key features:

• Accessibility Checker (Accessibility > Full Check) — runs 30+ checks for tags, alt text, language, headings, and more.
• Auto-Tag Document — creates initial tags; always review and fix manually afterward.
• Touch Up Reading Order — visual overlay with numbered content blocks.
• Tags Panel — full tree view for manual editing.
• Prepare Form — create and fix form fields with tooltips.
• Action Wizard — batch processing multiple files.

// Acrobat JavaScript to run the full accessibility check
var results = this.runAccessibilityCheck();
if (results.length > 0) {
    console.println("Issues found:");
    for (var i = 0; i < results.length; i++) {
        console.println("- [" + results[i].severity + "] " + results[i].description);
    }
}

pa11y-pdf

An open-source Node.js tool for automated PDF accessibility checking, suitable for CI/CD integration.

# Install pa11y-pdf
npm install -g pa11y-pdf

# Check a single PDF
pa11y-pdf report.pdf

# Output example:
# {
#   "pageUrl": "report.pdf",
#   "issues": [
#     { "code": "WCAG_TAG_001", "type": "error", "message": "Document is not tagged" },
#     { "code": "WCAG_LANG_001", "type": "error", "message": "Document language not set" },
#     { "code": "WCAG_ALT_001", "type": "warning", "message": "Figure missing alt text" }
#   ]
# }

// Programmatic pa11y-pdf usage
const pa11yPdf = require("pa11y-pdf");

async function checkPDF(filePath) {
    const results = await pa11yPdf(filePath);
    console.log("Issues found:", results.issues.length);
    results.issues.forEach(issue => {
        console.log(`${issue.type}: ${issue.message}`);
    });
    return results;
}

checkPDF("monthly-statement.pdf");
// Example output:
// "Issues found: 4"
// "error: Document is not tagged"
// "error: Document language not set"

Other Notable Tools

Common Mistakes

1. Relying on a single checker — Different checkers catch different issues. Use at least two (e.g., Acrobat's built-in checker + PAC 2021).

2. Auto-tagging without review — Acrobat's Auto-Tag creates initial tags but often produces incorrect heading levels, wrong reading order, and flat table structures.

3. Ignoring warnings — Many tools distinguish errors from warnings. Warnings like "Possible reading order issue" are often real problems.

4. Not testing with a screen reader — Automated checkers cannot verify that content sounds correct. Always test with NVDA or JAWS.

5. Batch processing without individual review — Action wizards automate checks but cannot fix semantic issues. Each PDF still needs human review.

Practice and Challenge

1. What is the difference between Acrobat's Accessibility Checker and PAC 2021?
2. How does pa11y-pdf integrate into a CI/CD pipeline?
3. Why is auto-tagging insufficient for PDF accessibility?
4. Which tool would you use to check PDF/UA compliance?
5. What is the role of screen readers in the PDF testing workflow?

Challenge: Take a sample PDF and run it through three different checkers: Acrobat's Accessibility Checker, pa11y-pdf, and PAC 2021. Compare the results. Which issues appear across all tools and which are unique to each? Write a report comparing the three tools.

FAQ

Mini Project

Set up a test environment with Acrobat Pro, pa11y-pdf, and PAC 2021. Create a 3-page PDF with intentional issues: missing tags, no language, one image without alt text, and a low-contrast paragraph. Run all three tools on the PDF. Compare the outputs and create a cross-reference table showing which tool found each issue.

What's Next

Proceed to PDF Accessibility Checkers for a detailed comparison of validation tools, then finish with PDF Accessibility Module Project.