Redaction goes wrong in a predictable way: someone draws a black rectangle over a name, sends the PDF, and the recipient selects the text under the box and copies it. It has happened in court filings and government releases. The box looked final, but the text was still in the file.
What proper redaction means
Real redaction removes the sensitive content itself, not just its appearance. If you can still select, search or copy the words after redacting, the job isn't done.
How the Redact PDF tool works
Redact PDF lets you draw solid black boxes over the areas you want to hide. Those boxes are drawn on top of the page. On their own they do not delete the text underneath, so treat the tool as step one of a safe workflow, not the whole workflow.
A safe workflow
- Work on a copy. Keep your original untouched.
- Draw the boxes. Open Redact PDF, upload the file and cover every sensitive item: names, account numbers, addresses, signatures, ID numbers. Be generous with the size of each box.
- Download the redacted file.
- Flatten it into images. Convert the redacted PDF to images with PDF to PNG, then rebuild a PDF from those images with PNG to PDF. Now each page is only a picture with the black boxes baked in.
- Test the result. Open the final PDF, press Ctrl+A or try to select text, and search for a word you redacted (Ctrl+F). Nothing sensitive should be found or copied.
- Optional: make it searchable again. If people need to search the rest of the document, run OCR PDF on the flattened file. The black-boxed areas are just black pixels, so the hidden words can't come back.
Redacting a multi-page document is slower this way, so plan for it and check every page. If you're working on one page of many, use Extract Pages to isolate it, redact and flatten it, then Merge PDF it back into place.
What to look for beyond the visible text
- Metadata. Author names and document titles can sit in the file properties. Check them and remove sensitive details.
- Comments and annotations. Remove them, or use Flatten PDF so they can't be pulled apart from the page.
- Repeats. A name in the header, footer and body needs covering everywhere.
- File names. "Smith_settlement_final.pdf" gives away what redaction was meant to hide.
When to be extra careful
Legal disclosures, medical records, HR files, data-protection requests and anything covered by regulation deserve a second reviewer and your organisation's approved process. Our tool can help you produce a flattened, image-based copy. It cannot promise legal compliance, so check the rules that apply to you.
Frequently Asked Questions
Is a black box the same as redaction?
No. A box hides text visually. Unless the text is removed or flattened into an image, it can often still be copied.
How can I test a redacted PDF?
Try to select the covered area, copy and paste it into a text editor, and search for the hidden words. If anything appears, it isn't safe to share.
Does converting to images reduce quality?
Slightly, depending on resolution, but it is a reasonable price for safety. Compress the result afterwards if it becomes large.
Can redacted text be recovered after flattening to images?
The hidden words are gone from the file's text layer, and the covered pixels are black. Use solid, opaque black and never a semi-transparent shape.