In my black and white photography class, the teacher recommends us to use ISO 400 to develop our film and make prints. I found that ISO 400 is much too grainy for my liking, and as a result I want to move down to something like ISO 100 or ISO 200.
My question is, does this affect at all the development and printing processes? Can I still use the same materials to develop, for the same amount of time as the ISO 400 film (like wise for the printing)?
I am using Ilford HP5 ISO 400, I want to use Ilford ISO 100