I'm interested in marking up a PDF in the same way a young person's teacher will mark up his essay. I want the markings to be permanent. How can I do that? Some of my PDFs are scans, so I was thinking, just extract the images, mark them up in the GIMP, and re-PDF them. If there is in fact an image layer in the PDF, I'd like to extract the images without conversion.
Edited by PA292, 24 February 2014 - 10:52 AM.