Just playing around with some old shaws film and processing it in B&W ... it's fun and frustrating, I wouldn't try this if you're wet printing but with a scanner you can get some good results if you expose properly. I have only done this with old film, so I don't have as much experience with new, I only do this with film I would otherwise throw away.
Seems to work best with 200 speed film rated at 50 ... I tried 400 speed rated at 100 and at 50 and it just didn't have the same consistency or look, not sure why.