Redact a PDF on your Mac so the text is really gone
By Himanshu Ranjan · Updated 8 November 2026
To redact a PDF properly on a Mac, select it in Finder, hold the right Option key and choose Sign & Lock › Redact text… FileDial turns matching pages into images with black boxes, then re-OCRs them, so the hidden words are actually removed rather than covered. Use Check redactions to test a file someone else redacted. Everything runs on your Mac, with nothing uploaded.
How to do it with FileDial
- Select the PDF in Finder and hold right ⌥.
- Choose Sign & Lock › Redact text… and enter the words to remove, or Sign & Lock › Find and redact personal info… to let FileDial look for them.
- If the PDF already has black boxes drawn on it, choose Sign & Lock › Burn in redactions instead.
- Run Sign & Lock › Check redactions on the result and read the .txt report.
- Share only the redacted copy that appears beside the original.
Your original file stays untouched. The result is saved beside it, and every result has Undo.
Which option to pick
| Tool | Use it when |
|---|---|
| Redact text…Sign & Lock | You know the words to remove: matching pages become images with black boxes, then are re-OCRed. |
| Find and redact personal info…Sign & Lock | You want FileDial to find personal details; you get a redacted copy plus a .txt of what kinds were removed. |
| Check redactionsSign & Lock | Before sending or after receiving: writes a .txt report of text still hidden under black boxes. |
| Burn in redactionsSign & Lock | Someone drew black boxes already: those pages become pictures, re-OCRed, so the hidden text is really gone. |
Why a black box is not a redaction
A PDF page is built in layers. The text is stored as characters, and anything you draw with a markup or comment tool sits on top as a separate object. Drawing a black rectangle over a name hides it on screen, but the characters are still in the file. Anyone can often select the area and copy it, search for the word, or remove the rectangle. This is one of the most common ways confidential details leak from documents that looked redacted.
Real redaction means the underlying text is gone. FileDial does this by turning each affected page into an image with the boxes burned in, then running OCR again so the rest of the page stays searchable. The removed words simply do not exist in the new file. Check redactions works the other way: it reads a PDF and reports any text still hiding under black boxes, which is worth running on any file before it goes to a court, a landlord or a journalist.
- Metadata can leak too: author names and edit history live outside the visible page.
- Search the redacted copy for the removed words before sending it.
- Pages that became images are a little larger and lose selectable vector text, which is then rebuilt by OCR.
Why not redact on a website?
To redact online you first have to upload the unredacted document, the very version you are trying to protect. Medical records, court filings and HR investigations are exactly where that is unacceptable. Cybernews reported in July 2024 that PDF Pro and Help PDF left Amazon S3 storage open, exposing 89,062 user-uploaded files including passports, IDs, certificates and contracts, and that the providers did not respond.
The FBI Denver Field Office warned in March 2025 that free online document tools can scrape personal data such as identity numbers and banking details. FileDial redacts on your Mac with Wi-Fi off if you like.
Other ways to redact on a Mac
Preview's markup tools can draw filled shapes, but those are annotations and the text underneath can remain, so they are not a safe way to redact. Some recent versions of Preview include a dedicated redaction feature; if you use it, verify the result by searching for the removed words or running a checker.
Printing to PDF does not reliably remove hidden text either, because many print paths keep the text layer. FileDial is the safer choice when the stakes are real: burned-in redactions, automatic personal-info detection with a report of what kinds were removed, a separate check, and the original kept intact beside the copy.
Questions
Is drawing a black box in a PDF enough to redact it?
Usually not. A drawn box is a separate object over the text, which often remains copyable and searchable. FileDial's Burn in redactions turns those pages into pictures and re-OCRs them, so the hidden text is really gone.
How can I check whether a PDF was redacted properly?
Select it and choose Sign & Lock › Check redactions. FileDial writes a .txt report of any text still hidden under black boxes. If it finds some, run Burn in redactions to remove it.
What does Find and redact personal info remove?
It looks for personal details and produces a redacted copy, with affected pages turned into images and re-OCRed, plus a .txt listing what kinds of information were removed. Review the copy before sharing it.
Does redaction work offline?
Yes. All FileDial tools run on your Mac and work with Wi-Fi off. The unredacted file is never uploaded, which matters most for exactly the documents people redact.
Will the redacted PDF still be searchable?
Yes, apart from the removed words. Affected pages become images and are then re-OCRed, which restores a searchable text layer for the rest of the page.