mbaumann
Hello,
I’ve been wondering for a while now what the best temperature is for C-41. 38°C is, of course, the standard processing temperature. However, it is possible to develop at 30°C or 24°C (and, as far as I know, at 45°C too).
The obvious disadvantage is the time involved. For example, here are the times I have from a Tetenal data sheet (for 3–4 films and a fresh batch):
Temperature/°C: 38 --- 24
Developing/min: 3:35 --- 18:30
Stopping/min: 0:30 --- 0:30
Bleach-fix/min: 6 --- 12
Rinsing/min: 3 --- 7
Stabiliser/min: 1 --- 1
When I develop, I usually do 2–4 passes for films in a Jobo CPE2. Time isn’t an issue there, and I don’t mind if it takes longer.
However, I see two major advantages to development at 24°C. Firstly, the difference from room temperature isn’t significant, so there are fewer fluctuations when I take the can out of the processor to pour in and out. And secondly, the relative time error during pouring in and out is lower. With a development time of 3 minutes 35 seconds, an error of, say, 15 seconds is significant, whereas at 18 minutes 30 seconds the impact is much smaller.
Both of these points suggest greater process stability at lower temperatures.
Hence my question to you:
Are there any other effects that argue against 24°C? For example, I could imagine that the longer exposure times might make it harder to wash out the chemicals, or that the long rinsing time could cause the emulsion to swell.
Do you have any experience or other helpful information on this topic?
Best regards,
Martin
haeberlein
Hello!
I develop using my CPE 2 (without the Plus) at just 25 degrees in the C41 process. However, I use Rollei chemicals, as there are tested times for them and the results are very good. At 38 degrees, I actually had the problem that I didn’t react quickly enough after pouring in the developer, so part of the film was developed slightly more than the other part, which unfortunately is visible in some of the colour photos.
Regards, Rene
