I'm getting ready to start processing my own 4x5 B&W negs in my bathroom. I processed all my film at school using Kodak Rapid Fixer that was always premixed and ready to go.(posted 8185 days ago)I recently got plain old Kodak Fixer (thats all it says on the package...though it says it in six languages) Having never used this before I know little about it. Does this have a hardening agent? Do I need one? Any different then Rapid Fix other then the fact that it takes longer? Any info would be great. I got this because B&H wasn't shipping the Rapid Fixer for some reason so I hope its what I'm looking for.