I have been playing around with pinhole cameras using photographic paper (instead of film). Great fun. But when I buy photographic paper, I don't seem to have any options for different ISOs, like I do with film. (I have 5" x 7" Ilford Multigrade IV RV paper.)
What I would really like is photographic paper that is less light sensitive, so I can do a longer exposures. Say, paper with an ISO of 5 instead of 100.
Is there any way to tell the ISO of photographic paper? Does anyone manufacture photographic paper with lower ISO ratings?