Are Black Boxes Appearing in Your PDFs? Here's How to Fix It!

This frustrating issue can disrupt document readability and professional presentation, leaving you wondering what went wrong.

The good news? Fixing it is easier than you might think, and we’re here to guide you every step of the way.

Below, we’ll explain the common causes of these black boxes and how you can fix them using Smallpdf's easy-to-use tools. Let's get your PDFs working perfectly again!

What Causes Black Boxes in PDFs?

The black box issue usually stems from a few common glitches. Here’s why it happens:

1. Missing or Unembedded Fonts

When the fonts used in your document aren’t embedded, your PDF viewer may not render the text properly. Instead, it could replace it with black boxes or incorrect formatting.

2. Corrupted Font Files

Damaged fonts or incorrect font encoding can confuse PDF readers, leading to rendering errors like black squares covering text.

3. Improper Redaction

Sometimes, black boxes are placed intentionally for redaction but aren’t properly executed. If the underlying text hasn’t been removed, this creates security concerns and visual clutter.

4. Rendering Glitches

Older or incompatible PDF viewers might misinterpret elements of the document, resulting in display issues like black patches.

Now that we know the causes, let’s fix the problem.

Steps to Fix Black Boxes in PDFs Using Smallpdf

1. Convert the PDF to Word to Fix Fonts

Not sure how to handle font problems? Use Smallpdf’s PDF to Word Converter.

• Visit PDF to Word Converter.
• Upload your troublesome PDF.
• Open the converted Word file and check if the fonts display correctly.
• Re-save the file as a PDF, ensuring fonts are properly embedded during the saving process.

This will resolve most font-related black box issues.

2. Edit the PDF to Remove Black Boxes

When fonts aren’t the issue, you can directly remove or edit the black boxes in your file using the Edit PDF Tool.

• Go to Edit PDF.
• Upload your file with black boxes.
• Use the editing tool to delete or replace the boxes as needed.
• Save and download your newly corrected PDF.

It’s that simple!

3. Compress the PDF to Enhance Performance

If your file is large or contains a lot of elements, performance issues could cause black boxes. Use Smallpdf’s Compress PDF Tool to optimize the file.

• Head to Compress PDF.
• Upload your file and choose from Basic or Strong compression.
• Download the optimized PDF, and enjoy improved rendering without glitches!

Additional Tips for Handling PDF Black Boxes

Here are some extra tips to prevent and troubleshoot black box problems:

• Update Your PDF Viewer: Make sure you’re using the latest version of your PDF reading software. Outdated tools are more likely to encounter rendering problems.
• Check for Software Conflicts: Try opening your PDF in different viewers or on another device. If the issue persists, it’s likely a file problem rather than a viewer issue.
• Ask the Document Creator: If you received the PDF from someone else, request a version with properly embedded fonts or corrected formatting.

Say Goodbye to Black Boxes for Good

Black boxes in PDFs can feel like a headache, but with the right tools, they’re surprisingly easy to fix. At Smallpdf, we aim to simplify your PDF experience. Whether it’s font embedding, editing, or compression, our tools have you covered.

FAQs About Fixing Black Boxes in PDFs

How do I fix black boxes in a PDF?

You can fix black boxes in a PDF with Smallpdf’s Edit PDF. Start by checking for font issues. If fonts aren’t embedded, use the PDF to Word tool, correct the file in Word, and re-save it as a PDF. Alternatively, edit the file directly using the Edit PDF Tool.

How can I put a black box over text in a PDF?

To intentionally place a black box over text for redaction, use our PDF Annotator. Draw a black rectangle over any sensitive sections and flatten the PDF to make it secure.

Why are my text boxes blacked out in PDFs?

This happens when fonts are corrupted, unembedded, or not supported by the PDF viewer. Follow the steps above to check and resolve font-related problems.

Can black boxes reappear after fixing them?

Not if the fonts are embedded correctly and the file is optimized. Always save a copy of your fixed PDF to avoid losing your edits.

How do I remove a black block from a PDF?

Open your file in the Edit PDF Tool. Click on the black box to select it, then press the delete key or use the trash icon. Once you're done, save the file to download your clean, updated PDF.