[liberationtech] Removing watermarks from pdfs (pdfparanoia)

[Eugen Leitl]

On Tue, Feb 05, 2013 at 06:59:03PM -0500, liberationtech at lewman.us wrote:
> On Tue, 5 Feb 2013 14:20:22 -0600
> Bryan Bishop <kanzure at gmail.com> wrote:
> 
> > How about removing those pesky watermarks from pdfs? Sometimes they
> > completely obfuscate the contents of a paper we're trying to read, or
> > sometimes they have more sinister purposes.
> 
> I get PDFs watermarked to me by their placement of sections in relation
> to one another, their word choice in opening sentences of paragraphs,
> and figure/image locations within the PDF. The idea being that the
> content is the watermark, not some silly overlay watermark which is
> fairly easily stripped out in most free operating systems.

If you render to bitmap, and then to djvu (maybe with OCR) then
this should strip these.