We have a watercolour that was mounted to a piece of mat board by the artist (over 40 years ago) which needs its framing renewed. After pulling the backing off, I find the mat board is badly warped (part of the reason it needs renewal it turns out.) The mat in front (separating the work from the glass) seems to follow the backer.
Should I try to flatten the mounts or just make sure all is secure in the frame? (Or take it to a pro?)