I believe Tillman Crane has masks created by a print shop for a clean edge when coating or exposing pt/pd.
For Silver Chloride paper, eg Fomalux & Lodima, I use Rubylith for masking. Just cut out the size you want, then tape the sandwich of neg & mask to underside of contact printing glass.
That's what I'm thinking about doing. It seems to me that the only way to insure proper 'contact' between paper and negative, while doing 'contact' printing, (to insure sharp prints), is to use a mask of rubylith or maybe even opaque material. (I thought of using the black plastic that printing paper comes in, but am not sure how to get a 100% straight cut since it's so flexible.
My idea is to cut two pieces of Ruby Lith, like an L-shape, and then overlay them to create any size mask I need, rectangular or square, within the limitations of the contact printing frame, which is 12x16".
I'm really picky about print presentation, and absolutely want neat, crisp, straight, and clean edges on the paper, since the edge of the white border and print area is displayed in the overmat window. This is going to be interesting. The enlargements will be easy by comparison...
