I'm a big fan of puzzle and have already a lot of puzzle with the puzzle conventional adhesives (for the self-touch) glued together, which is a real mess. But these films are just awesome - with a little practice they are attaching super light and particularly Faltenfrei. You do not necessarily attach to the back of these films - the turning of large puzzle is not as easy. Have front mounted on the image side, the film. But to not see in the picture frame.
Real easy. I'll be able to call only on the films.