How To Mount a Print (About.com)
This is actually a pretty useful lesson for those looking to make a hinge-mounted mat.
Photographic prints should be mounted so they can be removed from the mount easily, and do not touch the glass if they are framed. This is done by using a window overmat. Cutting mounts requires special equipment and some practice, and although many photographers do mount their own prints, others are happy to leave the job to a professional framer. The advice here is still useful, as not all framers are trained to handle photographs.