I took a B&W film class last semester and have recently set myself up for work in the darkroom. I have only developed about 12 rolls of film in developer of questionable effectiveness. I have decided for costs sake to go with Arista brand chemicals for my learning curve and I'm trying to decide between the Efke iso50 or the Arista iso100 for my film (I'm looking at films that come in 2 1/4X3 1/4 size sheet). Any opinions as to what will work best? Anybody know any sources for the HP5 in the 2 1/4X3 1/4 size?