Many people hide private details in a PDF by drawing a black rectangle over them. That looks fine on screen, but the text underneath is often still in the file. Anyone can select it, copy it or delete the box. Real redaction removes the text itself.
Why simple black boxes fail
A PDF is made of layers. A shape drawn on top of text only covers it. The words remain underneath and can be copied into another document. Highlighting in black, changing the text colour to black or using a marker tool in a viewer can all leave the original text intact.
What people usually redact
- Account, card or ID numbers.
- Home addresses and phone numbers.
- Names of other people in a shared document.
- Salary, tax or medical details that are not needed by the reader.
Share only what the other side actually needs. If a page is not relevant, remove the page instead.
How to redact properly
- Open the Redact PDF tool.
- Add your PDF.
- Type the words or numbers you want to black out.
- Press Redact and download the result.
The tool blacks out the words you type and flattens the pages into pictures. Because the original text is no longer in the file, it cannot be copied or recovered. The trade-off is that the redacted PDF is no longer searchable.
Check the result before sending
Never trust a redaction until you have tested it.
- Open the new file and try to select the hidden area with your mouse.
- Press Ctrl+F (or Cmd+F) and search for a word you hid. It should find nothing.
- Look at every page, because a name may appear in headers, footers or several places.
- Spelling matters. If a number appears with spaces in one place and without in another, redact both forms.
Do not forget hidden details
Text on the page is not the only place private data lives. A PDF can carry an author name and title in its properties, so consider the metadata editor too. If your document includes photos, the Remove EXIF tool strips location data from the pictures before you add them.
Keep your original
Redaction is permanent in the new file, so always save it under a new name and keep the unredacted original somewhere safe. Never overwrite the only copy.
Privacy
The work happens in your browser, so the unredacted document is never uploaded. For sensitive files, that is the safest way to do it.