In December 2025, the Department of Justice released the Jeffrey Epstein files. The documents were supposed to be redacted. Names and sensitive details were covered with black bars. What the DOJ sent was a "masked" PDF, not a properly redacted one. The New York Times reported that the hidden text was recoverable. Lawyers and journalists extracted the supposedly protected information within hours.
This wasn't a sophisticated hack. It was a basic redaction failure, the kind that happens when people don't understand the difference between hiding information and removing it.
A major academic study analyzed nearly 40,000 PDF documents from 75 security agencies across 47 countries. The findings were striking: 65% of files claimed to be redacted still exposed hidden information. These weren't amateur operations. These were government agencies using industry-standard software, and they still got it wrong.
Mac users face particular confusion because Preview, Apple's built-in PDF viewer, offers redaction tools that look simple but require careful execution. Use them correctly, and the sensitive information is permanently removed. Use them incorrectly, and you've created a false sense of security while the actual data remains embedded in the file.
Here's how to redact PDFs on Mac correctly, where the native tools fall short, and what alternatives exist for production-grade redaction.
The short version: If you need to redact sensitive documents before they reach AI systems, PaperVeil handles that layer. The rest of this article explains where it fits in the broader governance architecture.
What Redaction Actually Means
Before diving into tools, the distinction between hiding and removing matters.
Hiding (not redaction). Drawing a black rectangle over text in a PDF adds a visual layer. The rectangle covers the text on screen and in print. But the underlying text data remains in the file. Anyone who opens the PDF in a text editor, uses "Select All," or employs basic PDF manipulation tools can recover what's underneath.
This is how Paul Manafort's lawyers failed during his federal prosecution. They submitted documents with black bars covering sensitive text. Journalists highlighted the black bars, copied, and pasted. The "redacted" information appeared in news reports the same day.
Actual redaction. True redaction removes the underlying data from the file structure. The text isn't hidden; it's deleted. The redaction mark replaces what was there. No recovery is possible because the information no longer exists in the document.
Preview's redaction tool performs actual redaction when used correctly. But the interface makes it easy to use the wrong approach.
Why This Matters for AI Workflows
The rise of AI document processing has made redaction more important than ever.
When you upload a PDF to ChatGPT, Claude, Gemini, or any AI assistant, the entire file content gets transmitted to external servers. If you've "redacted" a document by drawing boxes over sensitive text, the AI system receives both the boxes and the text underneath. Your Social Security number, client names, or proprietary data travel to third-party infrastructure despite appearing hidden in Preview.
Even properly redacted PDFs require care. Most redaction tools, including Preview, focus on visible text. They may not address:
- Document metadata (author, creation date, editing history)
- Embedded form field data
- Hidden layers in complex PDFs
- Comment and annotation data
- Revision history
A document that looks clean may still contain sensitive information in these hidden areas that AI systems can access.
Redacting PDFs in Mac Preview
Preview's redaction feature has been available since macOS Big Sur (macOS 11, released in 2020). If you're running an older macOS version, Preview won't have this capability.
Step 1: Make a Copy First
This cannot be emphasized enough. Once you redact and save a document in Preview, the original content is permanently gone. There's no undo after saving.
Before any redaction work:
- Duplicate the original file
- Name the copy clearly (e.g., "Document_REDACTED.pdf")
- Keep the original in a secure location
Step 2: Open the Redact Tool
Open your PDF in Preview. Access the redaction tool through either method:
Method A: Click the Markup button (pencil icon, top right), then click the Redact button (top left of the markup toolbar).
Method B: Choose Tools > Redact from the menu bar.
When you activate the redaction tool, Preview displays a warning dialog explaining that redaction is permanent. Read this carefully before proceeding.
Step 3: Select Content to Redact
With the redaction tool active, your cursor changes to a crosshair. Click and drag across the text you want to redact. A black bar with an X pattern appears over the selected area.
You can select multiple areas before saving. Each selection will be redacted when you save the document.
Step 4: Save to Make Redactions Permanent
Until you save, the redactions are provisional. The marked areas show the X pattern but the underlying text still exists.
Choose File > Save or press Command+S. Preview may prompt you about making the changes permanent. Confirm, and the redaction becomes irreversible.
What Not to Do
Don't use shapes. The Markup toolbar includes rectangle and other shape tools. Drawing a black rectangle over text is not redaction. It's the exact failure that exposed Paul Manafort's documents. Preview will actually warn you if you try to draw shapes over text, but users often dismiss warnings without reading them.
Don't rely on printing. Some users "redact" by drawing boxes, printing to PDF, and assuming the new file is clean. This doesn't work. The underlying text structure often transfers to the new PDF.
Don't assume you got everything. Preview's redaction tool works on text you can see and select. It doesn't find text for you or handle metadata.
Limitations of Mac Preview Redaction
Preview's tool is functional for basic redaction needs but has meaningful gaps.
No search and redact. If a document contains someone's name 47 times, you need to find and redact each instance manually. There's no "find all instances of X and redact" capability.
No pattern matching. Preview can't automatically detect Social Security numbers, phone numbers, email addresses, or other structured sensitive data. You need to know what you're looking for and find it yourself.
Metadata blindness. Redacting visible text doesn't touch the document's metadata. Author name, creation date, modification history, and other properties may reveal information you intended to protect. You need to remove metadata separately through File > Export.
No batch processing. Redacting one document at a time is manageable. Redacting hundreds of documents for a litigation matter or FOIA response becomes prohibitively time-consuming.
Image-based PDFs. If your PDF was created by scanning paper documents, the content exists as images, not text. Preview's redaction tool doesn't work on image content. You need OCR to convert images to text first, or you need to draw opaque boxes over image areas (which does work for images, unlike for text).
No audit trail. Preview doesn't generate logs of what was redacted. For compliance purposes, you may need documentation showing what sensitive information existed and that it was properly removed.
Third-Party Alternatives for Mac
When Preview's limitations become problematic, several alternatives offer more capable redaction.
Adobe Acrobat Pro. The industry standard for professional PDF work. Acrobat's redaction tool includes search-and-redact functionality, pattern matching for common sensitive data types, metadata removal, and batch processing. The $22.99/month subscription is significant, but organizations doing regular redaction often consider it necessary.
PDF Pen Pro. A Mac-native option at $129 one-time purchase. Includes redaction tools, OCR for scanned documents, and batch processing. Less capable than Acrobat but handles most common redaction needs without subscription pricing.
Redactable. A cloud-based service specifically focused on redaction. Offers AI-powered detection of sensitive data patterns, automatic redaction suggestions, and audit trail generation. Pricing scales with usage. The cloud-based approach means documents travel to external servers for processing, which may not suit all security requirements.
Command-line tools. Technical users can use tools like pdftk or qpdf to manipulate PDF structure directly. This approach requires understanding PDF internals but offers complete control over what gets removed.
Comparison Table
| Feature | Preview | Acrobat Pro | PDF Pen Pro | Redactable |
|---|---|---|---|---|
| Basic redaction | Yes | Yes | Yes | Yes |
| Search and redact | No | Yes | Yes | Yes |
| Pattern detection | No | Yes | No | Yes (AI) |
| Metadata removal | Manual | Integrated | Manual | Integrated |
| Batch processing | No | Yes | Yes | Yes |
| OCR for scanned | No | Yes | Yes | Yes |
| Audit trail | No | Yes | No | Yes |
| Price | Free | $22.99/mo | $129 | Usage-based |
For AI Workflows: The Automated Approach
Manual redaction doesn't scale for organizations processing documents through AI systems regularly. A support team handling customer documents, a legal department processing discovery materials, or a healthcare organization summarizing patient records needs automated detection and removal of sensitive information.
The pattern looks like this:
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Automated detection. AI-powered systems scan incoming documents for sensitive data patterns: names, numbers, addresses, dates, and custom patterns specific to your organization.
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Review interface. Human reviewers verify suggested redactions, adding any the system missed and removing false positives.
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Batch application. Approved redactions apply across document sets, with consistent handling regardless of volume.
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Audit generation. The system produces logs documenting what was detected and redacted, supporting compliance requirements.
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Clean output. Redacted documents are ready for AI processing, external sharing, or regulatory submission.
This approach inverts the traditional workflow. Instead of redacting after problems arise, you redact before documents enter AI systems, ensuring sensitive information never reaches external infrastructure regardless of which AI tools staff members use.
The Bottom Line
Mac's Preview app can redact PDFs properly, but only if you use the correct tool and understand its limitations. Drawing shapes over text creates dangerous false confidence. The redaction tool removes data permanently, but only for text you manually identify and select.
For occasional redaction of personal documents, Preview works fine. For business use, legal documents, or AI preprocessing workflows, the limitations become problematic quickly. No search capability, no pattern detection, no metadata handling, no batch processing, no audit trail.
The organizations getting redaction right aren't relying on native tools for production work. They're using purpose-built systems that automate detection, ensure comprehensive removal, and generate the documentation that compliance programs require.
Whatever tool you choose, the principle remains constant: test your redactions by trying to recover the "removed" text. Open the redacted PDF in a text editor. Try selecting and copying. Search for terms you thought you redacted. If you can recover anything, your redaction failed.
PaperVeil automates PDF redaction for AI workflows. Detect sensitive data with pattern matching and AI, apply redactions across document batches, remove metadata and hidden content, and generate audit trails. The redaction layer that makes document processing actually safe.