Redacting PDF Scans

[JennyB]

I have some PDF Scans of old computer magazines from the 1990's that I'd like to put online, but they contain some names and addresses and other private and probably out-of-date info that I'd rather not display.

Is there any easy way to black that out without rescanning?

[mouser]

That's a more interesting question than it may first appear -- there are surely easy ways to put a black bar over the information from within a pdf editor -- but you need to be very careful that the original text isn't still recoverable and contained within the pdf -- something that might be quite hard to figure out just on a casual examination of the file.  Lots of stories about how people thought they removed/hid some information in a document but found that the information was still present in the file.

[JennyB]

I don't have them to hand, but I think that most of them are image scans from pre-PDF days, not even OCRed. Does that make a difference?

[kunkel321]

If they started as paper docs and got converted to a PDF, I'll bet you can use a PDF tool to black out the parts, then REprint as a new PDF file and the blacked out info would be permanently gone.  I saw a PDF tool at dottech recently
http://dottech.org/freebies/27354/free-investintechs-sonic-pdf-creator-v3-0-limited-time-offer/
that probably can do the blocking.
I'm not sure if it does virtual printing, but you probably already can do that.  If not, check out the free http://www.cutepdf.com/Products/CutePDF/writer.asp

EDIT:  I'm not positive, but I think that even a Word file saved as pdf, then redacted as above and sent through a virtual printer would be secure.

[cmpm]

not even OCRed. Does that make a difference?

Yes, that would make it easy, if it's converted to a .png or .jpg.
Use ScreenshotCapture's editor or another editor that can blackout sections.
Then to be sure, take a screenshot of the finished product.

[bob99]

It's fun to go back and look at old computer & electronics magazine articles just to see how things have changed over time. I kept some from the '70s and it's amazing.

No one has said it yet though, I'd be careful what you put on-line.  Especially if any of it is copyrighted.  While your intentions are good, too many people today try to make money the "new-fashioned" way... litigation and lawsuits. 
Just a thought.

[kunkel321]

FYI there's a PDF OCR tool on http://www.giveawayoftheday.com/ today...

[Renegade]

not even OCRed. Does that make a difference?

Yes, that would make it easy, if it's converted to a .png or .jpg.
Use ScreenshotCapture's editor or another editor that can blackout sections.
Then to be sure, take a screenshot of the finished product.

+1

That's a good recommendation.

If it is OCR'd, you can remove text in an editor like Adobe Illustrator, then save the result.

However, you still have the potential for metadata to be present, so cmpm's recommendation that you take a screenshot of the final product is excellent.