How to Add an Alternate Description to PDF Figure Tags

Lucia Todova
Co-Founder | Chief Architect of PDFix Technology & Automation

Figures and images often contain critical information in a PDF – from charts and graphs to product photos and scanned documents. But without an alternate description, this content is invisible to people using screen readers. To comply with PDF/UA and accessibility requirements, every Figure tag should include an alternate description. In our latest video tutorial, we show you exactly how to add alt text in PDFix – both manually and automatically.

Why Alternate Desctiption Matters

• Clarity & context – Well-written descriptions make complex charts or diagrams understandable.
• Accessibility compliance – Required by PDF/UA, WCAG, Section 508, and EN 301 549.
• Better user experience – Screen reader users can understand figures without relying on visuals.

Options in PDFix for Adding Alt Text to Figure Tags

In the video, we demonstrate several approaches:

1. Built-in Set Alternate Description

• Enter a custom description manually.
• Reuse text from closest tags (captions, headings, nearby paragraphs).
• Extract text from behind the figure’s bounding box.

2. External AI Actions

PDFix supports external AI-driven actions for generating alt text automatically.

• Choose different AI models, such as OpenAI or BLIP
• AI suggests meaningful descriptions based on the figure’s content.
• Review and refine results as needed.

3. Batch Processing

• Select multiple files in Application View
• Run a built-in or external action to add descriptions to all figures at once.
• Filter which tags to handle (e.g., only Figures larger than 40×40 px).
• Save results with custom output names or directories.

Continuous AI Model Integration

In PDFix, we don’t limit you to a single AI model for alternate descriptions.
We are continuously adding state-of-the-art AI engines to deliver the best possible results. Let us know your preferred model, and we can integrate it into the PDFix pipeline.

Watch the Video Tutorial

👉 How to Add an Alternate Description to PDF Figure Tags

The video walks you step by step through manual, AI-assisted, and batch workflows so you can ensure every figure in your PDFs is properly described.

Best Practices for Figure Alt Text

• Keep descriptions short and meaningful.
• Don’t duplicate captions – instead, complement them.
• Skip purely decorative images.
• Always review AI-generated alt text before publishing.

Watch the Webinar: Generate Figure Alt Text, MathML & Table Summaries Automatically

Learn how to automate alt text generation for figures, convert formulas to MathML, generate table summaries, and fix annotation descriptions – from basic templates to AI models.