How to Blackout Text in a PDF (Permanently)

Need to blackout text in a PDF before sharing it? Maybe you're hiding a Social Security number on a bank statement, removing a client's phone number from a contract, or blacking out confidential information in a legal document before filing.

Here's what most people don't realize: the standard methods of "blacking out" text in a PDF don't actually work. Drawing a black box, using a highlighter, or adding shapes just hides the text visually—the actual content remains in the file, fully readable by anyone who knows where to look.

This guide shows you how to properly blackout text so it's permanently removed from the document, not just covered up.

Why Most "Blackout" Methods Don't Work

When you open a PDF in Preview, Adobe Reader, or most free PDF editors and draw a black rectangle over text, you're creating what's called an annotation layer. Think of it like putting a sticky note over text in a physical document—the text is still there underneath.

Here's what actually happens with common "blackout" attempts:

Method	What It Does	Is Text Removed?
Black rectangle/shape	Adds shape on annotation layer	❌ No — text is selectable underneath
Black highlighter	Changes text appearance	❌ No — text can be copied
Text box filled black	Adds annotation over content	❌ No — annotation can be removed
Screenshot & crop	Creates image, loses text layer	⚠️ Partial — metadata may remain
Print to PDF	Flattens visual appearance	❌ No — just hides layers
Proper redaction tool	Deletes text from file	✅ Yes — permanently gone

What True "Blackout" (Redaction) Means

Proper blackout—technically called redaction—doesn't just hide text visually. It permanently deletes the content from the PDF file structure. After true redaction:

• The text cannot be selected — there's nothing to select
• The text won't appear in searches — Ctrl+F finds nothing
• Copy/paste captures nothing — the data doesn't exist
• The file structure contains no trace — forensic tools can't recover it
• OCR layers are also cleaned — scanned document text is removed too

This is the only way to safely blackout sensitive information before sharing a PDF.

Method 1: AI-Powered Redaction Tools (Fastest & Most Reliable)

Modern redaction tools use AI to automatically detect sensitive information—SSNs, phone numbers, addresses, account numbers—so you don't miss anything. They also handle the technical complexity of properly removing text from all PDF layers.

How to Blackout Text with SafeRedact

Method 2: Adobe Acrobat Pro ($239/year)

Adobe Acrobat Pro includes a proper redaction tool, but it's buried in the interface and easy to use incorrectly. Here's the right way:

Step-by-Step in Adobe Acrobat Pro

1. Open your PDF in Acrobat Pro (not the free Adobe Reader—it can't redact)
2. Go to Tools → Redact
3. Click "Mark for Redaction"
4. Click and drag over the text you want to blackout
5. Critical: Click "Apply Redactions" in the secondary toolbar
6. Click "OK" when warned this is permanent
7. Save the document

Adobe's Hidden Dangers

Common Error	What Goes Wrong
Using shapes/comments instead of Redact tool	Text remains underneath, fully visible
Forgetting "Apply Redactions"	Marks are annotations only, text intact
Not running "Remove Hidden Information"	Metadata, comments, hidden text may remain
Redacting scanned PDFs without OCR cleanup	Hidden OCR text layer still searchable

Method 3: Mac Preview (Limited)

Mac's Preview app added a redaction feature, but it has significant limitations:

1. Open the PDF in Preview
2. Go to Tools → Redact (or use Markup toolbar)
3. Click and drag over text to blackout
4. File → Export as PDF (not Save—you must Export). Or convert with ModernPDF if you don't have Preview/Acrobat.

Preview's limitations:

• Only works on text-based PDFs (not scanned documents)
• No automatic detection of sensitive information
• No batch processing for multiple documents
• Doesn't clean metadata or hidden layers

For simple, single documents with clearly visible text, Preview works. For anything more complex, use a dedicated tool.

Method 4: Free Online PDF Tools (Risky)

Many free online "PDF editors" claim to offer blackout or redaction features. Be extremely careful:

Tool Type	Risk Level	Notes
Tools that upload to servers	🔴 High	Your sensitive documents on someone else's server
Tools using shapes/annotations	🔴 High	Don't actually remove text—just hide it
Browser-based (local processing)	🟢 Lower	File never leaves your device

If you need to blackout sensitive information, the document itself is sensitive. Think twice before uploading it to random websites.

How to Blackout Text in Scanned PDFs

Scanned PDFs are documents that started as paper and were photographed or scanned. They're trickier to blackout because they contain two layers:

1. The image layer — What you see (a picture of the document)
2. The OCR text layer — Invisible searchable text created by optical character recognition

If you only blackout the visible image, the hidden text layer still contains all the information—searchable and copyable.

To properly blackout scanned PDFs:

• Use a tool that handles both layers (SafeRedact and Adobe Acrobat Pro do this)
• The tool should redact the image AND remove the corresponding OCR text
• Verify by searching for known text after redaction

What Information Should You Blackout?

The specific information to blackout depends on your situation, but here are common categories:

Financial Documents

• Social Security numbers — Always blackout, or leave only last 4 digits
• Bank account numbers — Full account and routing numbers
• Credit card numbers — The full number, expiration, and CVV
• Income amounts — When not required for the recipient's purpose

Personal Identification

• Home addresses — Especially when combined with names
• Phone numbers — Personal mobile and home numbers
• Email addresses — To prevent spam or targeted attacks
• Dates of birth — A key component for identity theft
• Driver's license numbers — Unique identifiers

Business & Legal

• Client names — When confidentiality is required
• Proprietary information — Trade secrets, internal processes
• Settlement amounts — Often required to be confidential
• Witness information — In certain legal filings

How to Verify Your Blackout Actually Worked

Never assume your blackout worked—always verify. Here's a foolproof testing process:

Test 1: Try to Select the Blacked-Out Area

Open the saved PDF and click-drag across where the sensitive text was. If your cursor changes to a text cursor or you can select invisible text, the blackout failed.

Test 2: Search for Known Values

Press Ctrl+F (Cmd+F on Mac) and search for specific text you blacked out—like digits of an SSN or a name. If the search finds anything, the text is still there.

Test 3: Select All and Copy

Press Ctrl+A to select all content, then Ctrl+C to copy. Paste into Notepad or TextEdit. Check if any blacked-out information appears in the pasted text.

Test 4: Check Document Properties

In most PDF readers, go to File → Properties. Check for author name, company, creation software, and other metadata that might reveal information you wanted to hide.

Common Blackout Mistakes to Avoid

1. Using Drawing Tools Instead of Redaction

The most common mistake. Drawing a black rectangle, using shapes, or adding annotations does NOT remove text. It just puts something on top. This is how the Manafort court filing disaster happened—lawyers drew black boxes but the text was fully readable underneath.

2. Forgetting About Scanned Document Text Layers

When you scan a document, OCR creates a hidden text layer. Blacking out the visible image doesn't remove this invisible text. Anyone can still search for and copy the information.

3. Not Applying Redactions in Adobe

Adobe's workflow requires marking text for redaction AND then clicking "Apply Redactions." Many people only do the first step and think they're done. They're not.

4. Ignoring Metadata

PDF files contain hidden metadata: author name, creation date, software used, edit history, and sometimes even deleted content. Always clean metadata when sharing sensitive documents.

5. Inconsistent Redaction

If a Social Security number appears on pages 1, 7, and 23, you need to blackout all three instances. AI-powered tools find all occurrences automatically; manual redaction requires careful checking.

Frequently Asked Questions

Can blacked-out text be recovered?

If you used proper redaction tools, no—the text is permanently deleted from the file structure. If you just drew shapes or used highlights, yes—anyone can recover it by selecting, copying, or removing the overlay. That's not an exaggeration; it takes about 5 seconds.

What's the difference between "blackout" and "redact"?

In everyday language, they often mean the same thing. Technically, "redaction" specifically refers to permanently removing content, while "blackout" can mean either true removal or just visual hiding. When accuracy matters, say "redaction" and use proper redaction tools.

Can I blackout text on my phone?

Most mobile apps only let you draw on PDFs, which doesn't actually remove text. Use a browser-based tool like SafeRedact on your phone for proper redaction. The web app works on mobile browsers and processes files locally.

How do I blackout an entire page or section?

In most redaction tools, you can draw a selection box around the entire area you want to remove and apply redaction. This removes all text and images from that area while keeping the page structure intact.

Is it legal to blackout information on documents?

Generally, yes—you can redact your own documents before sharing them. However, you should never redact documents that have been subpoenaed, are part of legal proceedings, or that you're required to provide in complete form. When in doubt, consult an attorney.

Why do blacked-out PDFs sometimes have larger file sizes?

If you used shapes or annotations (the wrong way), the file grows because you're adding content. Proper redaction removes data and may slightly reduce file size. If your "blacked-out" PDF is larger, that's a red flag the blackout didn't work correctly.

Ready to Blackout Text in Your PDF?

SafeRedact makes it easy to properly blackout text, words, and sensitive information in any PDF. AI automatically detects things like SSNs, addresses, and phone numbers—or you can manually select exactly what to hide. Your file never leaves your browser, and the redaction permanently removes content from the document.