Sometimes it's not possible to select items which need to be redacted from a pdf simply by using the redact tool. For example, cursive signatures, diagrams, or faded text which aren't properly detected by OCR. I'm wondering if a workaround for this is to use the rectangle tool, set the fill color to black, and black out sections which need to be redacted, then print the pdf and select "pdf" as the printer name. No metadata would be saved, correct?
So let's say I mark up "PDF A" using this method, then print as pdf, saving as "PDF B." Would this give me the same result as printing a hard copy of "PDF A," redacting with a black marker, and then scanning back into the computer, making it 100% impossible for anyone to access the redacted material? Seems like common sense but I'm redacting some very sensitive material which is going to be uploaded to a public site and want to be certain.
I think it's safe to say that it would not give the same result and not provide any certainty that the faux redacted material is gone. Try doing that and then use the editing tools in Acrobat to remove the rectangle that was added.
I will state a good rule to observe quite strictly: unless you are an expert on PDF internals, and have the tools to analyse PDFs in detail DO NOT TRY TO CREATE ANY ALTERNATIVE ROUTE TO REDACTION. This was created for that special purpose because no other route was safe and reliable.
In this particular case, the original image will be hidden, but not removed; it would take an expert only a few seconds to remove the marker you put on top.
This technique has been used by many including the US government, to their great embarrasment.