the clean thin edge/line of the negative. i have also made
a "window" to print through to get a white edge and a black edge ...
i don't trim and drymount, ever ...
i cut a window and overmat and use those tiny archival clean negative
corners to hold the print down underneath.
i never print full bleed or almost no "buffer" around the print's edge and the edge
of the paper. even if i have the mat crop into the print a tiny bit, the last thing
i ever want is to have too little of an edge, and the corners i use to hold the print down
become visible in the window.