Image privacy redaction — Verify the result

Worked example

Reopen the saved file, zoom to 200-400% on every covered region and confirm no letter shape or digit can still be read.

Zoom to 200% and 400% on each covered area and ask one question: can any letter shape, digit or line of a signature still be recognised? At 18 px blocks, a large font can still show hints of ascenders; if you can guess even one character, go back, raise Pixel size and paint again.

Then check around the edges. Compare the covered area with the original side by side and make sure the blocks start before the first character and end after the last one. A stray letter peeking out at the end of a name is the most common leak, because the block grid snaps to the image, not to the text.

Look at everything else in the frame once more using your list: tab title, address bar, notifications, small footer text and reflections. Verify the file name and the folder path in any visible window too, since they can carry the same name you covered.

A frequent mistake is trusting how it looks at fit-to-screen size. Open the saved image in a different viewer, zoom in, and ask a colleague who has not seen the original whether they can read anything. If they can, the redaction has failed; if not, it is good enough for your risk level, which is a judgement only you can make.

Screenshot with a marked private region

Export with manually covered region

No check can guarantee irreversibility, so look at the saved file at 400% and decide with the sensitivity of the data in mind.