How to redact a PDF properly (and why black boxes often fail)

Every few months a court filing or government report makes the news because “redacted” names turned out to be readable. The cause is almost always the same: someone drew black boxes over the text. The box hides the words on screen, but the text is still in the file underneath — anyone can copy it out, or search for it.

How to check whether a redaction worked

• Search the PDF (Ctrl+F or ⌘F) for a word you redacted. If it’s found, it’s still there.
• Select the text around the black box and paste it into a note. Hidden text often comes along.
• Check the document properties: author names and comments can live in the metadata.

How to redact a PDF properly

1. Open Redact PDF and select your document.
2. Search for words or numbers to remove — every match is marked — or draw boxes over areas such as signatures, photos or addresses.
3. Review the marks on each page and remove any you don’t want.
4. Turn on “Also remove document metadata” to clear the title, author and other properties.
5. Click Redact PDF and download the result.

Each page with a redaction is rebuilt as a flat image with the black boxes burned in, so the covered content is gone for good. Pages without redactions keep their normal, selectable text.

Before you share

• Run the checks above on the redacted file.
• Use Clean PDF to remove attachments, scripts and hidden thumbnails — thumbnails can show a page as it was before redaction.
• If a redacted page should still be searchable, run OCR PDF on the result; the black boxes contain no text to find.

Keep the original, unredacted file somewhere safe. Redaction can’t be undone.