Security & Privacy
How to Black Out Text in a PDF So It Cannot Be Recovered
Hiding text and removing text look identical on screen and are completely different in the file. Here is how to do the one that actually works.
Blacking out text is one of those tasks where the obvious method — draw a black rectangle — produces something that looks exactly like the correct result and offers none of the protection.
The two methods, side by side
| Method | On screen | In the file |
|---|---|---|
| Draw a black shape | Text is hidden | Text is intact and copyable |
| Redact | Text is hidden | Text is deleted |
They are visually indistinguishable, which is precisely why the mistake keeps being made by people who are being careful.
Do it properly
- 1Open the Redact PDF tool and add your file.
- 2Drag a box over each passage to remove. Work visually from the page — no coordinates to type.
- 3Extend each box slightly beyond the text so no partial characters survive at the edges.
- 4Apply and download.
- 5Test by copying from the blacked-out regions.
Beyond the black boxes
Two things routinely survive an otherwise careful redaction.
The first is metadata: author, title, subject and producer fields, none of them visible on the page and all of them readable in one click. A document redacted to anonymise its author frequently names the author in its properties.
The second is the shape of what you removed. A redaction box exactly as wide as a name narrows the possibilities considerably, and in a short list it can identify the person outright. Where that matters, redact a uniform region rather than a tightly fitted one.
Print and rescan: the crude fallback
Printing a document, blacking out passages with a marker, and scanning the result destroys the information completely — there is no digital layer left to recover. It is ugly, it produces a large image-only file, and for a genuinely high-stakes disclosure it is unimpeachable.
Use it when the consequences of failure are severe. For everything else, proper redaction plus verification is the right balance.
Do it now
Redact PDF
Black out sensitive information. It runs in this browser tab — your file is not uploaded anywhere.
Open Redact PDFFrequently asked questions
Can someone recover text under a black box?+
Yes, trivially — by copying it, or by deleting the shape. Only redaction removes the content.
Does exporting to an image make it safe?+
It removes the text layer, so yes for the visible page — but the file becomes unsearchable, much larger, and unreadable by screen readers.
Should the box be exactly the width of the text?+
Prefer a uniform width. The length of a redaction can itself reveal what was removed.
What about the metadata?+
Clear it separately. It is not touched by redacting the pages.