I'm not convinced that there would be much difference between 2 inversions of the tank every 30 seconds compared to 4 inversions every minute. The total agitation is the same, just more spread out. If anything, I suppose the fourth inversion of the 4-every-minute might have less effect than the first, so this regime might give a little less overall agitation, giving lower contrast and slower speed.(posted 9379 days ago)When I try a new film/developer, I usually test it with my own regime (which is 5 inversions every 30 seconds for 35mm). It's bad enough keeping notes of different temperatures etc, I can't keep track of agitation regimes as well.