A full mortise hinge has one of its leaves mortised to a door's edge and the other to a cabinet face. This kind of hinge makes the door appear smoother. A lot of people prefer a full mortise hinge because it gives off a cleaner look. It also makes the fit between the frame and the door a lot tighter so the installation looks more professional. Aside from these things, this kind of hinge has more benefits to it than just the way it makes the door look. For instance, it's less likely that the hinge plates will twist and experience alignment problems because the edges are held securely in place. It's also something that you can install on your own and still make it look like professionals did the job.
Marking the Hinge
Trace the perimeter of the hinge and mark the middle part of the screw holes.
Cutting the Hinge
Cutting the hinge is done to get the hinge to the size you want it to. The mortise has to have the right thickness and must also fit squarely with the cabinet face. Do this with extreme caution.