I went to the exhibit of Magnum photographers at the Portland (ME) art museum today. For this exhibit, new prints of uniform size have been made from the original negs of the photographers, both living and dead. It was a fine exhibit, though I'd seen most of the photos before over the years.

However, as in many recent (last 5 years) photo exhibits I've seen both here and in Europe, the particular fashion for mounting and displaying prints is to have the print trimmed of borders, dry-mounted on the backboard, and then to have the window mat cut about 3/8 of an inch wider on all sides than the print itself. The edges of the beveled window mat do not overlap the edges of the print.

Anyone know when and why this fashion began, and if there's a particular rationale that makes it better than the old way of having the window mat overlap the print edges a bit? And what about the dry-mounting?