Redaction is the one PDF operation where getting it wrong has consequences. Organisations have published documents with black rectangles drawn over names, only for anyone to select the text underneath and copy it out. The box was an annotation; the words were still in the file.
Redact PDF removes the content rather than covering it. The characters and image data inside the marked area are deleted from the page's content stream, and an opaque block is drawn in their place. Copy the redacted area afterwards and you get nothing, because there is nothing left.
How to use Redact PDF
- 1Upload the document and use the full-page thumbnail rail to move between pages.
- 2Drag a box over every piece of information that must be removed.
- 3Work through the whole document — check headers, footers, page numbers and margins as well as the body.
- 4Apply redactions, which destroys the underlying content.
- 5Download the redacted file and verify by selecting and copying over the black areas.
Why covering is not redacting
A black rectangle drawn in an annotation tool is a separate object layered above the text. The text is untouched and can be extracted by anything that reads a content stream. True redaction rewrites the content stream so the characters no longer exist in the file.
Do not forget the metadata
Names and identifiers hide outside the visible page too: document properties, author fields, comments and revision history. After redacting, check the document properties. Running the file through PDF to PDF/A or a fresh re-save is a good way to strip stray metadata.
Always verify before releasing
Open the finished document, try to select text across each black area, and search for the words you removed. Thirty seconds of verification is the difference between a redacted document and a data breach.
Supported formats, limits and things to know
- Redaction is irreversible by design — always keep an unredacted master copy.
- Text in scanned images is removed as image data; run OCR first if you need to search for terms.
- Document metadata is not automatically scrubbed — check it separately.
- Encrypted files must be unlocked first.
Redact PDF — frequently asked questions
Is redaction the same as drawing a black box?
No, and the difference matters enormously. A black box is a layer over text that can still be copied. Redaction deletes the underlying characters from the file.
Can redacted text be recovered?
No. The content is removed from the page's content stream, which is why you must keep an unredacted original.
How do I check my redaction worked?
Open the output, try to select and copy across the black areas, and search the document for the removed words. Both should come up empty.
Does it redact scanned documents?
Yes — the image data in the marked region is removed. Run OCR first if you also want to search for the terms you are removing.
Does redaction remove hidden metadata?
Not automatically. Check document properties and comments separately before releasing the file.