How to Redact a PDF Properly (A Black Box Is Not Enough)

By NUR Technologies · October 28, 2026 · 5 min read

Many people “redact” a PDF by drawing a black rectangle over a name or an ID number. The text is still there underneath. Anyone can select it, copy it or reveal it. Here is why, how to check, and how to do it properly.

Why a black box does not erase anything

A rectangle you draw in a PDF editor or in Preview is a shape placed on top of the page. The text, or the image with the text, is still inside the file. Software can read it, and so can a person who selects the page, copies the text or removes the shape.

How to test your redaction

1. Select everythingOpen the redacted PDF and select all the text (Command-A).
2. Copy and pastePaste it into a text document. If the hidden words appear, they were never removed.
3. Search for the wordUse the search field in the PDF viewer to look for the hidden name or number.

How to do it properly

A real redaction removes the underlying content from the file. One way is to turn the affected pages into images and rebuild the PDF, so there is no text left to find. Rivet does this in its Redact tool: the text under the black box is erased from the file (the affected pages become images).

1. Open RedactDrop the PDF on Rivet and choose Redact.
2. Pick what to hideRivet can find emails, phone numbers, links, long numbers, CURP and RFC, and also your own words.
3. Save and testSave the copy, then repeat the copy-and-search test above on the result.