These are all on old (mid 80s I would guess) ORWO BS-1 paper. That paper is very difficult to keep from curling up while it dries. I should probably get some kind of press. But I also find that it results in very nice prints without much effort. The modern Ilford multi-grade RC paper I usually use is much more finicky and much more sensitive to exposure time variations. This isn’t very scientific but the ORWO paper just feels like it wants to do a good print.
Especially when exposing it a bit too long – the ORWO paper gets darker but without losing details where the Ilford would just turn black. (I think “ORWO BS-1” is the low contrast version, so it might just be that).
6×9 cm is on the small side for photos, but still very much usable without a magnifying glass. Reminds me of very old (1910s or so) photo albums – which makes sense because most of those would be contact prints from 6×9 box cameras, at least around here in Germany. The Plaubel Makina I used makes much sharper pictures, of course. So as a physical artifact these are kinda fun – they look like ultra high resolution historical photos. At least in person – on the scans one can zoom in far enough to see that they are not actually *that* sharp, really.