I have a .pdf book that has a stamp or watermark I want to get rid of. Every page has two layers, each with a copy of the same phrase. One of the copies on each page is visible on the bottom of the page. The other one is invisible, apparently placed vertically in the middle of the page. The book has 317 pages, and when I use Google Drive .pdf reader search it finds 634 results - every other result showing as a highlight of invisible text I wouldn't see otherwise.
However, Adobe only gets 317 layers and seaech results - the visible ones on the bottom of each page. It has no clue whatsoever of the hidden ones. I can delete the visible stamps (merge them into one layer and remove). Then, Adobe sees no stamps anymore. However, when I put the edited file into Google Drive .pdf viewer - the remaining 317 "invisible" layers and stamps are all there.
How to make Adobe find those remaining layers and delete them?
You probably need to contact the copyright holder to see if they will release you a copy without their stamps.
The book is in open access, digital copies are rarely available though and the one I found has been stamped by third party that had never held any rights to it in the first place.
What concerns me is the fact that Adobe Acrobat fails to recognise (let alone edit) some of the content that other, free programs can ser right away. Is adobe unreliable here or am I missing some feature that would make it work?