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Redacting a PDF or an image: what this tool does
This tool covers sensitive information in a PDF or an image with solid black bars. It finds ID numbers, IBANs, SWIFT/BIC codes, card numbers, phone numbers and e-mail addresses in the PDF’s text and suggests them; find and black out searches every page for a name, a company or a licence plate; and anything else you mark by dragging a box with your finger or the mouse. Whether you call it redacting, blacking out or censoring, it is the same job.
Your file is never sent to a server. The pages are read, painted and rebuilt in your browser, and nothing is left behind when you close the tab.
Why a black box alone is not enough
Draw a black rectangle over text in a PDF editor and the text is not deleted, only hidden: it can still be selected, copied and found with the search box. That is how many “redacted” documents have given up what was under the box.
This tool turns every page that carries a box into an image, paints the black bars onto that image and puts it in the page’s place. The text underneath is gone because the page is no longer text — it is a picture. There is no blur and no pixelation: blurred text can be read back with dedicated tools, so the only thing offered is flat, fully opaque black.
What it costs, and what it does not do
- On pages with a box, text can no longer be selected or searched. The page becomes an image and the file grows. Pages without a box are kept as they are, text included.
- No OCR. A scan or a photo has no text layer, so automatic detection cannot work; you draw the boxes by hand.
- Automatic detection is a helper, not a verdict. ID numbers, IBANs and card numbers are checked against their check digits; phone numbers and e-mail addresses are recognised by their shape; addresses are guesses and start switched off. Look through every page before you black anything out.
- No blur, no pixelation. Black bars only.
The output is checked
After building the file, the tool opens it again and reads it: it counts any text left on the pages that became images, searches the whole document for each value you blacked out, and looks at the document properties (author, title, XMP, attachments). The result card shows those counts as sentences; if a check does not hold, that sentence is not written and a warning is shown instead.
ID copy: front and back on one A4 page, with a note
Add photos of the front and back of an ID, black out fields the recipient does not need, and the cards are centred on an A4 page (crop a card to its edges and it comes out close to its real width of 85.6 mm). You can put a note such as “COPY – for … only” and a date on the card. A note in the margin is easy to crop off, so the note is repeated diagonally across the card instead. It is a common precaution and does not promise protection on its own.
For what to write and what you can cover depending on who asks: what to write on an ID copy.
How do I redact a PDF or an image?
Step 1: Open the file
Drop the PDF or the images. The PDF’s pages are read and the ID numbers, IBANs, phone numbers and similar items in its text are listed.
Step 2: Review what was found
Tick or untick each item; ticking one blacks it out on every page where it appears. Use “find and black out” for a name or a company.
Step 3: Mark the rest by hand
Draw boxes on the page; you can move, resize and undo them. On a phone, use “Scroll” to move around and “Draw box” to draw.
Step 4: Black out and read the check summary
Press “Black out and create PDF”. The summary on the result card says, in counts, what is and is not left in the output; check the box positions in the preview one last time.
Step 5: Download
Download the redacted file. Your original stays as it was.
Frequently Asked Questions
Is the text still there when I draw a black box on a PDF?
In most PDF editors, yes: the box hides the text but does not delete it, and it can be selected and copied. This tool turns the page into an image and paints the box onto the image, so the text under it is not in the file.
Why is a black box not enough, and why is there no blur?
A box covers the text but leaves it in the file. Blur and pixelation distort text without destroying it, and dedicated tools can read blurred text back. So the only thing offered is flat, opaque black.
Is my file uploaded to a server?
No. The tool has no endpoint that accepts files; everything happens in your browser. You can open the network tab and check for yourself: your file is in no request.
Does automatic detection work on a scanned PDF or a photo?
No. Those have no text layer, only a picture, and there is no OCR. The tool tells you so, and you mark the areas by drawing boxes.
Does automatic detection catch everything?
No, it is a helper. ID numbers, IBANs and card numbers are checked against their check digits; phone numbers and e-mails are recognised by shape; addresses are offered as guesses and start switched off. It can flag things it should not and miss things it should: look at every page before you black anything out.
How do you know the blacked-out values are really not in the output?
After building the file, the tool opens it again, extracts its text and searches for every value you blacked out. The result card only says “N blacked-out values cannot be read in the output” if the count shows it. For boxes you drew by hand there is no text to compare, so check them by eye in the preview.
What happens to pages without a box?
They are copied as they are and their text stays selectable. If you want no text left anywhere in the document, switch on “turn every page into an image”; it starts switched on for PDFs that contain form fields or notes.
Can I use it on a phone?
Yes. In “Draw box” mode you draw a rectangle with your finger; switch to “Scroll” to move around the page. Zoom in to draw a tidier box over small print.
Does writing a note on an ID copy commit anyone to anything?
It is a common precaution, not a guarantee and not something with legal effect. Its purpose is to make the copy harder to reuse for anything else.
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