Is there any formula to be able to convert times between temperatures? I want to do a massive pull, and at -30%/stop (secondary question, does -30% hold up for every single stop, or just the first 2?), I am afraid the first developer time becomes very short at 38 celsius, so I wan't to lower temperature. I've seen this formula for Xtol New time = Old time × exp(-0.081 × (New temp °C - Old temp °C)) But wasn't sure if this would universally apply to b&w style developers or not. I want to do at least a 4 stop pull to save this roll that's already exposed this way. But by -30% that would reduce time to 86 seconds.. assuming that's correct and highlights have been developed next to the cut off point created by the silver solvent which would also be much higher now..