PDF Redaction support

Help and frequently asked questions · Last updated 20 May 2026

What is PDF Redaction?

PDF Redaction is a macOS application that removes text and image content from PDF files. Unlike tools that draw opaque rectangles over content, PDF Redaction modifies the PDF’s content stream and image data directly, so the redacted content is no longer present in the output file — it cannot be recovered by switching viewers, selecting text, or extracting the raw stream.

Is PDF Redaction stable? What does the beta status mean?

PDF Redaction is currently in beta. The core redaction engine is feature-complete and every save is verified before completing, but the app has not yet had wide real-world exercise across every kind of PDF in the wild. Treat beta builds accordingly:

• Keep a copy of the original document.
• Review every redacted output in a separate PDF viewer before sharing it.
• Report anything that looks wrong — especially any case where verification fails, or where a redaction appears to remove the right region but text is still recoverable elsewhere.

How does redaction actually work?

Three layers of removal happen at save time:

• Text. Text-showing operators (Tj, TJ, ', ") whose glyphs intersect a redaction rectangle are deleted from the content stream. The text never re-renders and is not present in the raw stream.
• Images. For JPEG and Flate-compressed image XObjects, the affected pixels are blacked out at the bitmap level. For images in formats we don’t support partial-pixel redaction in (CMYK, 1-bit, Indexed), the whole image is replaced with a solid black rectangle as a safe fallback — see “An image was fully blacked out” below.
• Form XObjects. Redactions recurse into nested form XObjects with current-transformation-matrix tracking. Redactions placed on a page that references a shared template (letterheads, recurring footers) apply to the template too.

After the redacted file is written, PDF Redaction re-opens it and re-extracts text from the redacted regions. If anything remains, the save fails. See the overview page for more detail.

Where is my data stored?

The PDFs you open stay where you opened them from — PDF Redaction does not copy your input files anywhere. The redactions you draw and any search state are held in memory while the document is open, and discarded when you close the document or quit the app. Output PDFs are written only where you ask the “Save” dialog to put them.

PDF Redaction makes no network connections by default. An optional auto-update check can be enabled in Settings → Updates; if turned on, it makes one HTTPS request per launch to GitHub to look for a new version, and sends no PDF content, no telemetry, no user data. See the privacy policy for the full detail.

System requirements

• macOS 11 (Big Sur) or later.
• Apple Silicon (M1 or later) or Intel. PDF Redaction ships separate disk images for each — pick the one matching your Mac.
• Around 200 MB of free disk space.

How do I download the beta?

PDF Redaction is in public beta. Download the disk image matching your Mac’s processor:

• PDFRedaction-aarch64.dmg — Apple Silicon (M1, M2, M3, M4).
• PDFRedaction-x86_64.dmg — Intel Macs.

Not sure which one? Click the Apple menu → About This Mac. If the “Chip” or “Processor” line starts with “Apple”, choose Apple Silicon. If it mentions Intel, choose Intel.

Both disk images are signed with our Developer ID Application certificate and notarized by Apple.

How do I install it?

1. Double-click the PDFRedaction-aarch64.dmg (or PDFRedaction-x86_64.dmg) file to open it.
2. Drag the PDF Redaction app into your Applications folder.
3. Eject the disk image (drag it to the Trash, or use the eject button in Finder).
4. Open the app from Applications. On first launch macOS may take a few seconds to verify the notarization; this is normal.

What happens on first launch?

The first time you open PDF Redaction after downloading it, macOS will show a confirmation dialog that looks like:

“PDF Redaction” is an app downloaded from the internet. Are you sure you want to open it?

[Your browser] downloaded this file today at [time]. Apple checked it for malicious software and none was detected.

[Cancel] [Open]

This dialog is normal and expected — every app downloaded through a web browser triggers it on first launch, regardless of how cleanly it is signed. The reassuring line is “Apple checked it for malicious software and none was detected”: this is macOS confirming that the app’s notarization and signature both check out. Click Open and PDF Redaction will launch. macOS remembers your choice and will not show this dialog again on subsequent launches.

macOS says the app is from an unidentified developer

This is a different and rare warning. The wording you are looking for is one of:

• “… cannot be opened because it is from an unidentified developer”
• “… cannot be opened because Apple cannot check it for malicious software”
• “… will damage your computer”

None of these should happen with the disk image you download from our official link — the app and the disk image are both signed with our Developer ID Application certificate and notarized by Apple. If you do see one of them, please stop and email us at support@whiteforgetech.co.uk before bypassing the warning. It probably means you have an unofficial copy of the app, or that something happened to the download in transit. We’d rather investigate than have you click through a real security warning unnecessarily.

The friendly “downloaded from the internet, are you sure?” dialog described in the previous section is not one of these warnings — that one is fine to confirm.

How do I draw a redaction by hand?

Open a PDF, click and drag on the page to draw a rectangle. The rectangle’s contents are not redacted yet — nothing changes in the file until you click Save redacted…. You can:

• click a rectangle to select it (it gets a coloured outline);
• drag a selected rectangle’s edges to resize it;
• press Delete or Backspace to remove the selected rectangle;
• press Escape to deselect;
• use Clear page to remove every rectangle on the current page, or Clear all across the document.

How do I redact every occurrence of a string?

1. Open the document and click Find… in the toolbar (top right).
2. Type the string you want to redact.
3. The Find panel shows the match count and lets you click any match to jump to that page.
4. Click Redact all to convert every match into a redaction rectangle in one step. The rectangles will appear on each page; you can then add manual ones too, or remove specific ones, before saving.

Can I redact using a regular expression?

Yes. Toggle the Regex switch in the Find panel and your search text is treated as a regular expression (PCRE-compatible). This is useful for redacting things like email addresses, phone numbers, or reference numbers in bulk.

How do I check that a redaction actually worked?

Open the redacted output in a different PDF viewer (Preview.app, a web browser, or another editor). Try to select text in the redacted regions; try copy-paste. If nothing comes out, the redaction has succeeded at the content-stream level.

For peace of mind, you can also use pdftotext from the Poppler tools (available via Homebrew with brew install poppler) and grep the output for the strings you redacted:

pdftotext redacted.pdf - | grep "the-string-you-redacted"

An empty result means the text is not present in the file.

Verification failed when I saved — what does that mean?

The save was aborted. PDF Redaction re-opened the file it was about to write, re-extracted text from the regions you redacted, and found characters still present. Rather than silently producing a file that looks redacted but isn’t, the app refused to write it.

This usually points to one of:

• An unusual font encoding that the text-bounds calculation didn’t handle correctly.
• Text inside a complex Form XObject that the recursion missed.
• Text inside an annotation rather than the page’s content stream.

If verification fails repeatedly on a specific document, please report it — we want every verification-failure case so we can fix the underlying bug. Don’t share the document; send us a small reproducer that exhibits the same shape (font, encoding, structure) if you can.

An image was fully blacked out instead of just the rectangle — why?

PDF Redaction performs partial-pixel image redaction for JPEG and Flate-compressed image XObjects in DeviceRGB, DeviceGray, and ICCBased colour spaces. For images in CMYK, 1-bit (DeviceGray with BitsPerComponent 1), or Indexed (palette-based) colour spaces, partial-pixel redaction is not implemented, so the whole image XObject is replaced with a solid black rectangle of the same dimensions. This is intentional and is a safe-by-default fallback — we’d rather over-redact than under-redact.

If you hit this for a workflow where you really need partial-pixel redaction in one of the unsupported colour spaces, let us know which one. Adding support is feasible; it just hasn’t been a priority yet.

How do I report a bug?

Two channels, whichever you prefer:

• Public Issue tracker at github.com/whiten1968/PDFRedaction-downloads/issues. Faster for us to triage, and other users can see what’s being worked on. Don’t attach actual documents here — it’s a public repository.
• Email support@whiteforgetech.co.uk for anything you’d rather keep private (e.g. you need to attach a sensitive document to reproduce the issue).

Either way, please include:

• What you were doing when the problem happened;
• What you expected and what actually happened;
• Your macOS version (Apple menu → About This Mac);
• The PDF Redaction version (Settings → bottom of the panel).

If the bug only reproduces with a specific document, try to construct a small synthetic document with the same structural shape and share that. Send original documents only if we ask, and only via email.

How do I request a feature?

Open a Discussion on the downloads repo (Ideas category), or email support@whiteforgetech.co.uk. We read every request.

Contact

Whiteforge Technologies Ltd
support@whiteforgetech.co.uk

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