Don’t Leave Your Images Silent – Add Alt Text Like a Pro!

Why Alt Text Matters in PDFs

Have you ever wondered how visually impaired users navigate PDFs filled with images, charts, and graphics? Unlike sighted users who can instantly understand visual elements, individuals relying on screen readers need a way to access this information. This is where alt text plays a crucial role.

What Is Alt Text?

Alt text, short for alternative text, is a hidden description assigned to images, illustrations, and other non-text elements in a document. Screen readers detect this alt text and read it aloud, allowing visually impaired users to understand the content without seeing the images.

Why is it important?

  • Ensures PDFs are accessible to everyone.
  • Helps organizations comply with ADA (Americans with Disabilities Act) and WCAG (Web Content Accessibility Guidelines).
  • Makes PDFs more inclusive, improving the experience for all users.
  • Without alt text, screen readers will skip over images, leaving important visual information inaccessible to those who rely on assistive technology.

Who Benefits from Alt Text?

Alt text isn’t just for users with visual impairments—it also helps:

✔ People using screen readers due to low vision or blindness.

✔ Individuals with cognitive disabilities who benefit from additional text descriptions.

✔ Anyone using text-to-speech tools, such as voice assistants.

✔ Users in low-bandwidth situations where images may not load, ensuring they can still access critical content.

By adding alt text to images in PDFs, you’re not just making documents more accessible—you’re ensuring that everyone can engage with your content, no matter how they access it.

How Screen Readers Interpret Alt Text in PDFs

Screen readers play a crucial role in making digital content accessible to visually impaired users. When encountering a PDF, these assistive tools read text aloud and provide verbal descriptions of images, tables, and other non-text elements but only if alt text is included.

How Screen Readers Process Alt Text

Popular screen readers like JAWS (Job Access With Speech), NVDA (NonVisual Desktop Access), and VoiceOver (Apple’s built-in screen reader) use built-in accessibility features to recognize alt text in PDFs. Here’s how the process works:

1. Screen readers scan the document’s structure, identifying headings, text, and embedded objects.

2. When they detect an image, they look for alt text.

3. If alt text exists, the screen reader reads it aloud to the user.

4. If no alt text is found, the screen reader either ignores the image or announces it as a “graphic” without context, making the content confusing.

To ensure a smooth experience for users, it’s essential to provide clear, concise, and meaningful alt text for images in PDFs.

Writing Effective Alt Text: The Importance of Clarity

When writing alt text, brevity and clarity are key. A screen reader will read the alt text exactly as written, so it’s important to describe images in a way that provides useful information without unnecessary detail.

✔ Good example (for a graph showing sales growth):

  • “A bar graph showing a 20% increase in sales from 2023 to 2024.”

❌ Bad example:

  • “Graph with blue bars and a red line, numbers on the left, labels on the bottom.”

Informative vs. Decorative Images: What Needs Alt Text?

Not all images require alt text. Screen readers distinguish between informative and decorative images, so it’s important to categorize them correctly.

✔ Informative Images (Needs Alt Text)

  • Charts, graphs, and infographics (e.g., “Pie chart showing 60% of users prefer online shopping.”)
  • Diagrams and instructional visuals (e.g., “Step 1: Click the ‘File’ menu to open the document.”)
  • Photographs that add context (e.g., “A teacher helping a student with reading.”)

❌ Decorative Images (Should Be Marked as Artifacts)

  • Background images and borders
  • Icons that repeat text (e.g., a checkmark next to ‘Approved’)
  • Stock photos that don’t add new information

To ensure screen readers skip decorative elements, mark them as “artifacts” in PDF accessibility settings. This prevents users from being overwhelmed by unnecessary descriptions.

Screen readers provide visually impaired users with access to digital content, but without proper alt text, they cannot interpret images effectively. By writing clear and concise descriptions and properly marking decorative elements, you can make PDFs more accessible and ensure all users have an inclusive reading experience.

How to Add Alt Text in PDFs (Step-by-Step Guide)

Adding alt text to images in PDFs is essential for making documents accessible to visually impaired users. Whether you’re using Adobe Acrobat Pro, Microsoft Word, or an online tool like PDF4Sure, the process is straightforward. Below is a detailed step-by-step guide to adding alt text using different methods.

Method 1: Using Adobe Acrobat Pro

If you have Adobe Acrobat Pro, you can add alt text directly to an existing PDF using the built-in Accessibility Tools.

Steps to Add Alt Text in Adobe Acrobat Pro:

1. Open your PDF in Adobe Acrobat Pro.

2. Click on Tools in the top menu.

3. Select Accessibility > Set Alternate Text.

4. A window will appear, automatically detecting images that need alt text.

5. Click OK, and Acrobat will guide you through each image.

6. Enter a descriptive alt text for each image.

Example: “A bar chart showing annual revenue growth from 2020 to 2024.”

7. If an image is decorative, select “Mark as decorative” to have screen readers ignore it.

8. Click Save to apply the alt text.

📌 Tip: You can also add alt text manually by right-clicking an image, selecting Properties, and entering a description under the Tag tab.

Method 2: Using Microsoft Word (Before Saving as PDF)

If your document was created in Microsoft Word, adding alt text before exporting to PDF ensures it remains accessible when converted.

Steps to Add Alt Text in Microsoft Word:

1. Open your document in Word.

2. Right-click the image you want to describe.

3. Select Edit Alt Text from the menu.

4. In the Alt Text panel on the right:

Enter a short but informative description of the image.

Example: “A teacher reading a book to a group of students.”

If the image is decorative, check “Mark as decorative.”

5. Click Close once done.

6. Save your document as a PDF:

  • Go to File > Save As > Choose PDF.
  • Click Options and ensure “Document structure tags for accessibility” is checked.
  • Click Save.

📌 Tip: This method is best if you’re creating a PDF from scratch and want to ensure accessibility from the beginning.

Method 3: Using PDF4Sure (Online Tool for Quick Edits)

If you already have a PDF and don’t have access to Adobe Acrobat Pro, an online tool like PDF4Sure can help you add alt text easily.

Steps to Add Alt Text in PDF4Sure:

1. Go to the PDF4Sure website and select “Add Alt Text”.

2. Click Upload and select your PDF file.

3. The tool will scan for images missing alt text.

4. Click on each image and enter a descriptive alt text in the provided field.

5. If an image is decorative, check “Mark as decorative” to exclude it from screen readers.

6. Click Apply Changes and download the updated PDF.

📌 Tip: PDF4Sure is a great option for quick alt text edits without needing paid software.

Adding alt text in PDFs ensures that all users, including those relying on screen readers, can fully understand the content. Whether you’re using Adobe Acrobat Pro, Microsoft Word, or an online tool, the process is simple and can significantly improve accessibility.

Pro Tip: Always keep alt text clear, concise, and relevant—this makes it easier for screen readers to convey the right information without overwhelming users.

Writing Effective Alt Text for PDFs

Alt text plays a vital role in making PDFs accessible to individuals who rely on screen readers. Writing effective alt text ensures that users receive meaningful descriptions of images, charts, and other visual elements. Below, we’ll explore best practices, examples of good vs. bad alt text, and how to handle complex visuals like graphs and tables.

Best Practices for Writing Alt Text

When adding alt text, follow these key principles to maximize clarity and usability:

✅ Keep it short but descriptive

Aim for 125 characters or fewer, so screen readers can process the information easily.

✅ Describe what’s important in the image

Focus on the main message or function of the image rather than unnecessary details.

✅ Avoid redundant phrases

Don’t start with “image of” or “picture of” since screen readers already indicate that it’s an image.

✅ Use punctuation

A well-structured sentence improves readability for screen reader users.

✅ Be objective and clear

Avoid subjective words like “beautiful” unless they add meaningful context.

Examples of Good vs. Bad Alt Text

To understand what makes alt text effective, let’s compare some good and bad examples:

✔ Good: “A bar chart showing sales growth from 2020 to 2024.”

❌ Bad: “A chart.” (Too vague)

✔ Good: “A red apple with a green leaf on a wooden table.”

❌ Bad: “A nice apple sitting somewhere.” (Lacks clarity)

✔ Good: “A teacher reading a book to a group of children in a classroom.”

❌ Bad: “A classroom scene.” (Misses the key details)

How to Handle Complex Images Like Graphs and Tables

Some images contain more detailed data that can’t be easily summarized in a short alt text description. Here’s how to handle them:

1. Charts and Graphs

Graphs often display trends, comparisons, or data insights. Instead of describing the visual elements, focus on what the graph is showing.

✅ Best Approach:

  • Summarize the key insight of the chart in alt text.
  • Provide a detailed data summary in the document text or as a caption.

📌 Example:

✔ Alt Text: “A pie chart showing that 60% of users prefer online shopping, while 40% prefer in-store shopping.”

✔ Additional Text in Document: “According to the chart, a majority of users (60%) prefer online shopping, highlighting a shift in consumer behavior.”

2. Tables with Large Amounts of Data

Tables contain structured information, which can be difficult for screen readers to convey in a short alt text description.

✅ Best Approach:

  • Instead of adding all details in alt text, provide a summary of the key insights.
  • Use proper table tagging in PDFs to ensure screen readers can read row and column headers correctly.

📌 Example:

✔ Alt Text: “A table comparing laptop models by price, battery life, and screen size.”

✔ Additional Text in Document: “The table shows that Model A has the longest battery life (12 hours) but is more expensive than Model B, which lasts 8 hours.”

Writing effective alt text enhances accessibility by providing visually impaired users with clear and meaningful descriptions. By following best practices, keeping descriptions concise yet informative, and properly handling complex visuals, you ensure that all users can fully engage with the content in your PDFs.

Checking Alt Text in PDFs for Compliance

Ensuring that a PDF meets accessibility standards is crucial, especially for users who rely on screen readers. To verify that all images have appropriate alt text, you can use Adobe Acrobat’s Accessibility Checker, online tools like WAVE or PDF4Sure’s Accessibility Scanner, and manual inspection methods. Below is a detailed guide on how to check alt text compliance effectively.

1. Using Adobe Acrobat’s Accessibility Checker

Adobe Acrobat Pro offers a built-in Accessibility Checker that scans a PDF for missing alt text, improper tagging, and other accessibility issues.

Steps to Check Alt Text in Adobe Acrobat Pro:

1. Open the PDF in Adobe Acrobat Pro.

2. Click Tools > Accessibility.

3. Select Full Check under Accessibility Checker.

4. In the Report Panel, look for a section labeled “Alt text missing” under “Document.”

5. Click on each flagged issue to see which images need alt text.

6. To fix missing alt text:

  • Right-click the image and select Edit Alt Text.
  • Enter a clear, concise description of the image.
  • Mark decorative images as “Artifacts” to exclude them from screen readers.

7. Re-run the Accessibility Check to confirm all errors are resolved.

📌 Tip: Adobe Acrobat also allows you to manually navigate through tagged images by selecting Tags Panel and reviewing their descriptions.

2. Using Online Tools Like WAVE or PDF4Sure’s Accessibility Scanner

If you don’t have Adobe Acrobat Pro, online tools like WAVE (Web Accessibility Evaluation Tool) or PDF4Sure’s Accessibility Scanner can help verify alt text in PDFs.

Steps to Check Alt Text Using WAVE:

1. Go to the WAVE website and upload your PDF.

2. Run an accessibility scan on the document.

3. The tool will highlight:

  • Images missing alt text.
  • Images with redundant or unclear alt descriptions.
  • Untagged elements that might need alt text.

4. Click on each flagged issue to review and fix the errors.

Steps to Check Alt Text Using PDF4Sure:

1. Upload your PDF to the PDF4Sure Accessibility Scanner.

2. Click Scan for Accessibility Issues.

3. The tool will identify:

  • Missing alt text in images.
  • Improperly marked decorative images.
  • Other accessibility errors like missing tags.

4. Use the built-in editor to add missing alt text and download the corrected file.

📌 Tip: Online tools are useful for quick compliance checks, but they may not catch every issue—manual review is always recommended.

3. Ensuring No Missing Alt Text in Important Images

Even after using automated tools, a manual review is essential to ensure:

✅ All important images have meaningful alt text.

✅ Decorative images are marked as artifacts.

✅ Complex images (charts, graphs, tables) include appropriate descriptions in the document text.

📌 Final Tip: Compliance isn’t just about having alt text—it’s about having the right alt text. Always ensure descriptions are clear, accurate, and helpful for visually impaired users.

Common Mistakes & How to Fix Them

Adding alt text to images in PDFs is essential for accessibility, but it’s easy to make mistakes that reduce its effectiveness. Below are some of the most common errors and how to fix them.

Mistake 1: Skipping Alt Text on Important Images

❌ The Problem: Many PDFs contain charts, infographics, and essential visuals that convey crucial information, but sometimes these images are left without alt text. When this happens, screen reader users miss out on important details.

✅ The Fix:

  • Ensure that all non-decorative images have alt text.
  • Use Adobe Acrobat’s Accessibility Checker to find missing alt text.
  • If the image is purely decorative, mark it as an artifact so screen readers skip it.

📌 Example Fix: Instead of leaving an infographic without alt text, write:

✔ “An infographic illustrating the rise in global internet usage from 2000 to 2024.”

Mistake 2: Writing Too Much or Too Little

❌ The Problem:

  • Too much detail: Writing long paragraphs in alt text makes it hard for screen reader users to follow.
  • Too little detail: A vague alt text like “A chart” does not provide useful information.

✅ The Fix:

  • Keep alt text under 125 characters (1–2 short sentences).
  • Focus on the most important details of the image.
  • Avoid unnecessary phrases like “Image of” or “Picture of.”

📌 Example Fix:

❌ Bad: “A picture of a bar chart with five different colored bars representing sales figures.”

✔ Good: “A bar chart showing annual sales growth, with a 25% increase from 2023 to 2024.”

Mistake 3: Forgetting About Tables & Graphs

❌ The Problem: Tables, graphs, and complex data visuals need more than just a basic alt text description. If you only write “A table of sales data,” it doesn’t help screen reader users.

✅ The Fix:

  • Use summaries for complex images instead of trying to describe every detail in alt text.
  • For tables, ensure they are properly tagged so screen readers can navigate row and column headers.
  • For graphs, add a brief alt text and then include a detailed description within the document.

📌 Example Fix:

✔ Alt Text for a Pie Chart: “A pie chart showing that 60% of customers prefer online shopping over in-store shopping.”

✔ Detailed Description in the Document: “The pie chart indicates that a majority of customers (60%) prefer online shopping, while only 40% prefer in-store shopping, based on a survey of 5,000 participants.”

Properly written alt text improves accessibility and ensures that visually impaired users can fully engage with your PDF content. Always review alt text manually to catch these common mistakes!

Conclusion

Alt text plays a critical role in PDF accessibility, allowing screen reader users to understand visual content. Whether it’s charts, infographics, or simple images, adding clear, concise descriptions ensures that all users can engage with your document.

Recap of key takeaways:

✔ Always check PDFs for missing alt text using Adobe Acrobat or online scanners.

✔ Use brief but meaningful descriptions for important images.

✔ Mark decorative images as artifacts so they don’t disrupt screen reader users.

✔ If a PDF lacks alt text, you can edit it in Adobe Acrobat Pro or modify the original document and resave it as a PDF.

💡 Final Pro Tip: Before finalizing your PDF, run an accessibility check to catch any alt text issues. This ensures a seamless reading experience for everyone, regardless of ability!

FAQs

When it comes to alt text in PDFs, many people have questions about how to check, edit, and properly apply it. Below are answers to some of the most common concerns.

1. How do I check if a PDF has alt text?

✅ Method 1: Using Adobe Acrobat Pro

1. Open the PDF in Adobe Acrobat Pro.

2. Click Tools > Accessibility.

3. Select Full Check and look for errors related to missing alt text.

4. Alternatively, open the Tags panel (View > Show/Hide > Navigation Panes > Tags) and check if images have alt text attached.

✅ Method 2: Using Online Tools

  • Upload your PDF to PDF4Sure’s Accessibility Scanner or WAVE (Web Accessibility Evaluation Tool).
  • The tool will flag images without alt text or improperly tagged elements.

2. Can I edit alt text in an already saved PDF?

Yes! If you have an existing PDF, you can still add or modify alt text.

Using Adobe Acrobat Pro:

1. Open the PDF and go to Tools > Accessibility.

2. Click Set Alternate Text and edit the descriptions for images.

3. Save the PDF with the updated alt text.

Using Microsoft Word (if the original document is available):

1. Open the Word document used to create the PDF.

2. Right-click an image > Edit Alt Text.

3. Save as PDF again, ensuring the accessibility settings are enabled.

3. What happens if I don’t add alt text?

❌ If you skip alt text, visually impaired users using screen readers won’t know what the image represents. This makes the document inaccessible and non-compliant with ADA and WCAG standards.

🚨 Risks of missing alt text:

  • Legal implications for organizations that must meet accessibility standards.
  • Poor user experience for people relying on assistive technology.
  • Reduced inclusivity and engagement with the document’s content.

4. How do I mark an image as decorative?

If an image is purely decorative (e.g., a background graphic or separator), you should mark it as an artifact so screen readers ignore it.

Using Adobe Acrobat Pro:

1. Open the Tags panel.

2. Find the image, right-click, and select “Change Tag to Artifact”.

3. Save the PDF.

Using Microsoft Word (before saving as PDF):

1. Right-click the image > Edit Alt Text.

2. Check the box that says “Mark as decorative”.

3. Save as a PDF.

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