Hi gang - I always presoak for a minute (with never a problemo) because that's the way I was taught many moons ago.(posted 9393 days ago)I now have a reason of my own. Several of the films I use have dark dyes that I am glad to see washed down the drain after my presoak. It just goes against my grain to pour fresh chemicals in on top of those dyes that are lurking there begging to be washed off. My negs look great too by the way so I've never had a concern that the dye was connected to good processing results.
Water is a chemical too, right? But B&W has so much latitude that it's been no biggie - for myself, at any rate. Aloha, Paul ;<)