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How to Permanently Redact a PDF, and Why Black Boxes Aren't Enough

InkOut PDF Team · Published 2026-10-20 · Last updated 2026-10-20

To permanently redact a PDF, you have to remove the sensitive text, images and hidden data from the file, not just cover them. Use a real redaction tool, apply the redactions, remove the metadata, save the result as a new file, and then test it: search for the redacted words and try copying the blacked-out areas. If you only draw a black box, the text usually stays in the file and anyone can copy it.

Why black boxes aren't enough

A PDF page is built in layers. When you draw a rectangle or highlight text in black, most editors add a new object on top and leave the original text underneath. The page looks redacted, but:

  • selecting the area and pasting it into a text editor reveals the words;
  • searching the PDF still finds them;
  • the shape can be moved or deleted in any PDF editor.

Courts warn filers about exactly this. The U.S. District Court for the District of New Jersey says that "highlighting text in black or using a black box over the data in MS Word or Adobe Acrobat will not protect the data from being able to be seen," that changing the text color to white is "similarly ineffective," and that "previous revisions and deleted text may be able to be seen" (D.N.J.).

Two real failures

TSA screening manual (2009). The Transportation Security Administration posted a 93-page screening procedures manual on FedBizOpps, a federal contracting website, with sensitive sections blacked out. According to Wired, the black rectangles were only laid over the text, so "anyone can uncover the hidden text by simply copying and pasting the blacked out portions" (Wired; CNN). A later review by the DHS Office of Inspector General found that "the redactions were not applied properly, and appropriate quality control procedures were not in place" (DHS OIG report OIG-10-37).

Paul Manafort court filing (2019). In January 2019, a filing by Paul Manafort's lawyers was published with redactions that didn't work. The BBC reported that the mistake "allowed anyone to view the text beneath blacked out sections of the online documents," revealing details of prosecutors' allegations that he had lied to investigators (BBC News).

Neither case involved hacking. Both files were simply shared with the text still inside.

What "permanent" redaction actually removes

A thorough redaction deals with three things:

  1. Visible content. The text and images under the redaction box are deleted, or the page is rebuilt without them.
  2. Hidden content. Metadata (author, title, keywords), comments, attachments, bookmarks, form data, hidden layers and earlier revisions. Adobe's list of redactable data types is a useful checklist (Adobe Help).
  3. The file you send. Save the result as a new file (for example Contract-REDACTED.pdf) so you can't send the original by mistake. The D.N.J. page recommends the same.

How to permanently redact a PDF: 3 ways

Option 1: In your browser with InkOut PDF (no install, no upload)

  1. Open inkoutpdf.com and choose your PDF. It stays on your device.
  2. Draw boxes over everything you want to remove. On PDFs with real text, Pro can find a word or number and mark every match. Scanned pages have no text to search (InkOut PDF has no OCR), so box those areas by hand.
  3. Export. InkOut PDF rebuilds each redacted page as a flat image with the boxes burned in, inside a new PDF that doesn't carry over the metadata, form fields, attachments or JavaScript. It then re-opens the file, checks the redacted pages for extractable text and scans the whole output file for the text you covered before you download.

Trade-off: redacted pages become images, so their text can no longer be selected or searched. Pages you don't redact keep their original text, but links and form fields on them stop working.

Option 2: Adobe Acrobat Pro

Select All tools › Redact a PDF, mark the content, select Apply, and turn on the option to sanitize and remove hidden information (Adobe Help). Redaction is part of Acrobat Pro, not Acrobat Standard (Adobe). See our InkOut PDF vs Acrobat comparison.

Option 3: Preview on a Mac

Preview's Markup toolbar has a Redaction Selection tool. Apple says it removes selected text from view and that "once you close the document, the redaction becomes permanent." Apple also notes that table-of-contents entries linking to redacted text aren't removed (Apple Support). Shapes drawn with Preview's other markup tools are annotations, not redactions. More in how to redact a PDF on a Mac.

Avoid: drawing shapes or highlights; changing text to white; cropping (cropped content can stay in the file); "printing to PDF" without removing the text first.

How to check that a PDF is really redacted

Do this on the exported file, every time:

  1. Search (Ctrl+F or Cmd+F) for a word or number you redacted. It shouldn't be found.
  2. Select and copy the area under each box and paste it into a plain-text editor. Nothing should appear.
  3. Check the document properties for an author, title or keywords you don't want to share.
  4. Or run the file through the free InkOut PDF redaction checker. It looks for text that can still be extracted from under dark boxes, with no page limit and no upload.

FAQ

Does drawing a black box over text in a PDF redact it?

No. In most editors the box is a separate object on top of the text, which can still be copied, searched or uncovered by moving the box.

How can I tell if a PDF was redacted properly?

Search the file for the redacted words and try to copy the blacked-out areas. If anything comes back, the redaction failed. A redaction checker can automate part of this.

Can redacted text be recovered?

Not if the content was actually removed. Text that was only covered by a shape, a highlight or white font color can be recovered easily, which is what happened in the TSA and Manafort cases.

Do I need Adobe Acrobat Pro to redact a PDF?

No. Acrobat Pro has a redaction tool, but InkOut PDF (in your browser) and the Redaction Selection tool in macOS Preview can also remove content. Whichever you use, check the exported file.

Does redaction remove metadata?

Not always. Some tools only remove the marked content, so make sure the metadata is removed too. Acrobat's sanitize option does this, and InkOut PDF doesn't carry metadata over into the exported file.

Sources (checked 2026-10-20)

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