This post includes a quick how-to tutorial and an entire kit in a .zip file to get you started right. To simply watermark your documents, all you need is my .pdf files in the kit and a couple of free apps from the Ubuntu Software Center. If you want to change the way I’ve laid it out, I’ve also included the GIMP source file so you can just open it, swap out the stamp you want with what I’ve done and export it to .pdf, followed with Bob being your Uncle.
*Note: the source file *must* be a PDF to overlay it in the new PDF
*Note: be careful about your output file name. It’s very easy to accidentally over-write your source PDF with the stamped one which you might not want to do. I recommend saving to a totally different folder called ‘watermarked’ or ‘stamped’ or something.
HERE IS THE KIT
Hope that helps and keep on spreading Ubuntu!