You point out one of the foibles of my paper construction methods, Wayne - the exposed corner. One could very likely mount the paper such that it would be possible to "wrap" the edge, covering the exposed matt board, but sometimes the scanned graphics are a bit mucked up. I usually do a bit of editing using MS Paint, creating a sliver I can cut and fit as a corner. It's not the best solution, but it generally works:

Of course, sometimes my diabetes-riddled eyesight fails me and I don't get things quite aligned properly when cementing the paper corner in place (as seen here). Still, in the world that was predominantly lithographed tab-and-slot construction, it works well enough for me.