I don't add the hardener to my fixer. But the one time I did put some prints face down I saw a distinct screen pattern later when I toned them. I assume the contact with "anything" made the surface a little "harder" than the emulsion that didn't touch anything. My screens are not your typical window screen material. They are made from super lightweight mosquito net mesh leftover from a camping gear sewing project. Since I consider freedom from screen patterns one of the unique beautiful characteristics of analog photography, the result of even a hint of screen turned my stomach. So for me, face up is my strong recommendation.
Originally Posted by Doc W