How to properly redact a PDF

Why a black box isn’t enough

In a PDF, the text and whatever is drawn on top of it are separate elements. When you add a black box with an ordinary editor or an annotation tool, it covers the text on screen, but the text often remains underneath.

• Simply copying and pasting the area can bring the hidden text back.
• The PDF reader’s search still finds the “hidden” word.
• The box can sometimes be moved or deleted by the person who receives the file.

Redacting means removing the information from the file, not just covering it.

What the “Redact PDF” tool does

Every page where you’ve drawn at least one area is converted to an image, with the black boxes built in. The text under the boxes isn’t copied over: it’s truly gone from the file, along with anything drawn in that spot (a signature or a photo, for example).

The rest of the text on those pages is kept invisibly, so you can still search for a word. Pages without boxes are kept as they are.

Redact a PDF step by step

1. Open the “Redact PDF” tool and select your document.
2. Click and drag on the page to draw a box over each area to hide. Move from page to page with the ◀ ▶ buttons.
3. To hide a name or number everywhere, type it in “Automatically hide a text” and click “Hide”: every occurrence is hidden, regardless of capitalization or accents.
4. Check the areas: the ✕ button removes a box, “Clear all” removes them all.
5. Click “Redact and save”, then download the redacted PDF.

The original isn’t modified: you get a new file whose name ends with “_redacted”.

Tips so you don’t miss anything

• In a scanned document, the automatic search finds nothing because there’s no real text: the tool shows “Text not found”. Draw the areas by hand instead.
• Go through every page before saving: a number written with spaces or dashes can slip past the search.
• Think of less visible information: headers, footers, signatures, file numbers.
• Open the resulting PDF and try to copy or search for the hidden text to make sure it’s really gone.

Redact, edit or protect?

These three needs look alike, but they’re not handled with the same tool:

• “Redact PDF”: permanently hide part of the content before sharing the document.
• “Edit PDF text”: correct or replace text, for example a wrong date or amount.
• “Protect PDF”: prevent the whole document from being opened without a password.

In every case, processing happens in your browser: your confidential documents never leave your device.