How to redact a PDF so the text is really gone
A black box drawn over text in a PDF often hides nothing: in many editors the text is still under the box and can be copied out. To redact properly, the page has to be rebuilt so the text is not in the file at all. PDF Redactor does that by redrawing each redacted page as a picture with the boxes painted into the pixels, and it runs in your browser.
Steps
- Open https://oddbits.tech/pdf-redactor/ and choose "Choose a PDF". One PDF at a time, up to 100 pages. A PDF that needs a password to open can't be read.
- Look through the page preview. To black something out by hand, switch on "Drawing boxes: on" and drag a box over it. "Drawing boxes: off (scrolling)" lets you scroll the page instead.
- To find a word everywhere, type it under "Or search for text" (the box says "A name, number or phrase") and press "Find". Tick "Match case" or "Whole word" if you need to. Use "Redact all" for every match, or "Redact and show" for one at a time.
- Look at every box in the preview. Where a search match sits inside a line is estimated and padded, so check that it covers the words and no more. The "Boxes" list lets you "Show" or "Remove" each one.
- Press "Redact and save", then "Download the redacted PDF". The file is named like yourfile-redacted.pdf.
- Check it worked (see the next section) before you send it.
Do it here: Redact a PDF. Runs in your browser: your PDF is not uploaded.
Check the result yourself
Open the saved file and try to select the hidden text. Search for a word you hid. Or run pdftotext on the file and search its output. If the word is there, do not send the file.
What this does not do
- It does not find everything. Search only sees text the PDF contains: a scanned page has none, so draw boxes there. The report says which pages have no selectable text.
- Redacted pages become pictures: you can't select text on them, and the file can get bigger.
- It does not keep your document information, XMP metadata, bookmarks, form fields or attachments: the saved file is a new document without them.
- It does not give legal advice or meet a legal redaction standard. If a court or regulator requires a specific process, follow theirs.
Questions
Why not just draw a black box in a PDF editor?
In many editors the text is still under the box and can be copied out. Here a page with a box on it is drawn again as a picture with the box painted into the pixels, and that picture replaces the page, so the text under the box is not in the file.
Can I redact a scan?
Yes, by drawing boxes. Search cannot find text that is only a picture.
What happens to pages I do not redact?
Where the tool can keep a page with confidence, it stays as live text. A page with comments, form fields, an inline image, a Type 3 font or anything it cannot check is drawn as a picture too, and the report lists those pages and why. You can also choose "Turn every page into a picture".
Why is my redacted file bigger?
Redacted pages are pictures now, drawn at twice their size. Fewer redacted pages means a smaller file.