I'm planning on trying the PVA-glue trick to mount some FB prints to board:
- dilute PVA glue 1:1 with water
- brush onto board, allow to dry
- slap wet print onto board, roll out bubbles
- print adheres, dries and shrinks onto board for flat finish

But I can't tell if any of the glues available locally have antifungal agents in them. How about mixing the glue with C-41 stabiliser (at working strength) instead of plain water? Will that have the anti-biological properties that I want for an archival framed print?

I've seen the process recommended for use on masonite since it's pretty rigid, but I worry about volatile glues used in the masonite degrading the image. What about thin (3-5mm) marine-grade plywood: plenty of antifungals in it but does it contain anything that's problematic for silver prints?

I'm going to try mat board as the backing too but I suspect the print shrinkage will distort the board.