OCR PDF on Windows

This turns out to be fairly easy.

1. Install Tesseract.
2. Convert your PDF to TIFF. Either print it (Print > Fax > check “print to file” and save as TIFF), or install Ghostscript and convert on the command line (I installed the 64 bit version):

gswin64c -r300x300 -o out.tif -sDEVICE=tiffg4 in.pdf

3. Convert the TIFF to a searchable PDF:

tesseract input.tif out -l deu pdf

Skip the -l deu bit if it’s not in German. out is the name of the output file; the extension (pdf here) is appended.

Done. You can even get Google to translate the output.