Can a redacted PDF be un-redacted?

Not when the text was truly removed: nothing is left in the file to recover. When a black shape was only drawn over the text, yes: the text can be copied, searched or uncovered by deleting the shape.

Is highlighting text in black a redaction?

No. A highlight or a drawn rectangle is a layer above the page. The text below it stays in the file and can be selected, copied and found by search.

Does flattening a PDF make a black box safe?

Not by itself. Flattening makes a drawn box part of the page so it can’t be moved or deleted, but the text under it is still in the page and can still be copied or searched. Only redaction removes it.

Can I redact a scanned PDF?

Yes. A scan is a picture with no text to search, so mark the area by dragging over it. The redacted page is saved as a new picture with the marked part painted black.

Do I have to upload my PDF to redact it?

No. Redact in PDF Case runs in your browser and the file stays on your device. Uploading a document to a server in order to hide something in it would expose the unredacted original first.

How to redact a PDF so the text is really gone

To redact a PDF for good, the text under the black box has to be deleted from the file, not just covered. Use a redaction tool that rebuilds the page without the text, then check the copy: search for the word, select everything and paste it elsewhere. A rectangle drawn on top does none of this.

Updated November 14, 2026

Why doesn’t a black rectangle remove the text?

A PDF page is a list of things to draw: text, pictures, lines. A black rectangle, a highlighter set to black or a filled shape from an annotation tool is one more thing drawn above the text. The text is still in the file, underneath, exactly as it was.

Anyone who gets the file can reach it in ordinary ways:

Select the text under and around the box, copy it and paste it into any other app.
Search the document for the name or number: the reader finds it behind the box.
Click the rectangle and delete or move it, when it is a comment or a shape that was never made part of the page.
Save the document as plain text, which leaves out the drawings and keeps the words.

What does true redaction do?

True redaction changes the content of the page, so that what was under the mark no longer exists in the file. There is nothing left to copy, find or uncover, because the letters are not there.

Redact in PDF Case does it by turning every page that has a mark into a picture of that page, black where you marked it. The page’s original text and drawings are dropped from the file. A word you find with the search is also taken out of the places a page picture would miss: form fields, comments, links and bookmarks. Before the copy is handed to you, the tool checks that the word is no longer in it, and gives no file if it still is.

The price is that a redacted page is a picture: its remaining text can no longer be selected or searched. Pages without a mark stay as they were.

How do I redact a PDF in this app?

The file is opened and redacted in your browser, on your device. It is not uploaded, which matters for the kind of document that needs redacting in the first place.

Open Redact and choose the PDF.
Type a name or number into the search and mark every place it is found, or drag over the part of the page to black out. On a scanned page there is no text to find, so drag.
Look at each mark. The search also matches inside longer words, so “Ann” is found in “annual”.
Leave “Remove document info too” on if the author, title or bookmarks could repeat what you are hiding.
Press Redact and download the copy. Your original stays as it was, so send the copy and not the original.

How do I check that the text is gone?

Check the redacted copy before sending it, whatever tool made it. Open it in a PDF reader and try what a curious recipient would try:

Search for the word or number you removed. It should not be found.
Select all on the page, copy, and paste into a text editor. The hidden text should not appear.
Click on the black area. It should not be an object you can select, move or delete.
Open the document’s properties and read the title, author, subject and keywords.

What else in the file can leak the same information?

Metadata is the second leak. The document’s details can hold the author’s name, a title such as “Offer for Jane Smith”, and dates; bookmarks and attached files can repeat the very thing that was blacked out on the page. Redact removes these when its switch is on; Remove metadata does the same job for a file that needs no black boxes.

A redaction does not hide the shape of what was removed. The length of a black bar, and the words around it, can still tell a reader what kind of thing was there.

Tools for this

Files are processed on this device and never uploaded.

Questions

Can a redacted PDF be un-redacted?: Not when the text was truly removed: nothing is left in the file to recover. When a black shape was only drawn over the text, yes: the text can be copied, searched or uncovered by deleting the shape.
Is highlighting text in black a redaction?: No. A highlight or a drawn rectangle is a layer above the page. The text below it stays in the file and can be selected, copied and found by search.
Does flattening a PDF make a black box safe?: Not by itself. Flattening makes a drawn box part of the page so it can’t be moved or deleted, but the text under it is still in the page and can still be copied or searched. Only redaction removes it.
Can I redact a scanned PDF?: Yes. A scan is a picture with no text to search, so mark the area by dragging over it. The redacted page is saved as a new picture with the marked part painted black.
Do I have to upload my PDF to redact it?: No. Redact in PDF Case runs in your browser and the file stays on your device. Uploading a document to a server in order to hide something in it would expose the unredacted original first.