E-6 First Developer Temperature and Pulling.

[Athiril]

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..

 

[oldfaithful58]

I don't know whether this applies to all E6 chemistry, but the Tetenal info quotes "3 stop pull -> 1st Dev time unchanged, reduce temperature to 28.6C ....2 stop pull, same time, temperature 30.6.
It may be possible to just extrapolate that -2C change -> 4 stops would be 26.6C The remaining steps should be at normal E6 temperatures.
Hope this helps
Dave

 

[Athiril]

Thanks it's a starting point, perhaps I can use 28.6 and reduce time a little.

Cheers