You're sharing a contract publicly but need to hide names and figures. The temptation: draw a black rectangle over them. The problem: the text is still in the file underneath, copy-pastable by anyone. Real redaction is more thorough.
Why black rectangles aren't enough
A black box drawn on top of text is an annotation, not a removal. The underlying text remains in the file. Anyone can select it, copy it, or remove the rectangle in an editor. This has caused real-world leaks — sensitive court documents, classified reports — when 'redactors' painted over instead of cutting out. Cover is visual; redact is structural.
True redaction removes content
Proper redaction deletes the underlying text or image data, then replaces the area with a solid block. After saving, there's nothing to recover — no hidden text, no copy-able layer, no metadata. Redact PDF in Flint does this properly: select what to remove, save, and the secrets are gone. Always work on a copy so the original stays intact in case you need to revisit.
Don't forget metadata and attachments
Text on pages isn't the only place secrets hide. PDF metadata can carry author names, edit dates, original filenames. Attachments inside the PDF stay even after page redaction. Before sharing a redacted file, also strip metadata and remove any internal attachments. A final save in Flint cleans both. For genuinely sensitive material, view the redacted file in another app first to verify nothing slipped through.
FAQ
Can someone undo a true redaction?
If the redaction tool removes content properly and the file is saved, no — the data is gone. But if the tool only hides content, recovery is trivial. Always verify with a tool that explicitly says 'redact', not just 'mark up'.
What about the text under a photo?
If a name appears in a photo (e.g., on a screenshot), redacting only the text layer doesn't help — the image still shows it. Cover or replace the image region itself.
Should I flatten after redacting?
Yes — flattening locks the redaction into the page so no annotation layer remains. It's a belt-and-braces step that prevents accidental future edits.
If it matters, redact properly. Open your file in Flint's redact tool and remove — don't just cover — the sensitive bits.