C41 Process Temperature

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Carl Hall

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The Tetenal kit that I've used in the past says that the standard processing temperature is 38 degrees, but the "alternative" temperature is 30 degrees. Apart from an increased development time, is there any other effects or issues from using the lower temp? I'm designing my own water bath and I'm hoping to use a regular aquarium heater instead of the purpose built Novatronic heater to keep the overall costs down, but they only go to about 35 degrees usually.
 
Carl Hall said:
The Tetenal kit that I've used in the past says that the standard processing temperature is 38 degrees, but the "alternative" temperature is 30 degrees. Apart from an increased development time, is there any other effects or issues from using the lower temp? I'm designing my own water bath and I'm hoping to use a regular aquarium heater instead of the purpose built Novatronic heater to keep the overall costs down, but they only go to about 35 degrees usually.
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Hi Carl, I must admit that despite developing hundereds of c41 films in years gone by I have always done them at the higher temperature. As you know film development is a chemical reaction and the hotter the liqueds the faster that reaction takes place. The most important part is the first one, the developer, you can usually do the following baths a few degrees cooler. So carrying out the process at a lower temp. means a longer time for the reaction to takes place. I do not know if it will effect the quality but I would think it would be worth running a couple of cheap rolls through the process at the lower temp, my guess would be there would not be much difference but I may, of course, be wrong.......
 
Hi Carl - I don't have any experience of running C41 at lower temperatures, but I've read a lot of threads on the subject over on APUG. At some point, the 'photo engineer' guy (ex Kodak, I believe) usually steps in and says that C41 must be run at 100F. Running it at a lower temperature apparently doesn't activate the colour couplers in the right way, so the results may be outside of spec. I believe the effect could be an overall colour cast, or a crossed cast with something like cyan highlights and magenta shadows. I've also seen discussions around the subject of whether lower temp C41 could affect the archival colours. I can't remember what the result of that discussion was.

Basically, if you run it at a lower temp you have to accept that you could run into colour shifts, although they may be very subtle.
 
"Wing it" Carl:D

I've used the tetenal kit several times now and not only will it develop more films that it states, the 30 degree temp ( it's the only one i've used) works perfectly ok and tbh the temp hasn't always stayed constant.
For eg, I've prewarmed the dev tank usually to a degree or two abpve 30, then added the developer, again perhaps a degree or two over. The developing tank has been sat at the side of the sink during it's required time so innevitably lost temperature ( i duuno how much as i haven't bothered to check it) ...the blix has been added at approx 30 degrees, wash at appprox 30 degrees and the stab at about 20 i would guess.

The first couple of times I used this kit I was glued to thrermometer readings, the dev tank in a bath of water which I was stressing out over it it dropped a half degree.
The results I got then were no beteer or worse than the results I get now when I'm somewhat "relaxed" about it all.

If there is any sight colour cast then one click on the eyedropper in PP and the jobs sorted.
 
Asha said:
the blix has been added at approx 30 degrees, wash at appprox 30 degrees and the stab at about 20 i would guess.
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I guess it isn't any help with what you're trying to do, but just FYI, the developer is the only step which is temperature critical. The bleach and fix can be a a couple of degrees either side of 35C and the stabiliser just has to be warm.

Asha said:
If there is any sight colour cast then one click on the eyedropper in PP and the jobs sorted.
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Agreed...unless you end up with a crossed colour cast. I had this happen with a couple of rolls of movie stock I used last year, and frankly, it was a huge pain. Took me hours in Photoshop/Lightroom to get close to removing the casts. It's not worth the potential extra effort for the sake of a few quid on a better heater.
 
Thanks for all the replies everyone :) I think I'm going to end up going for the proper Novatronic heater. Chances are that I'd be perfectly ok at the lower temp and not see any noticeable difference (by my untrained eye at least), but it's one less variable to have to contend with!

Just done some quick maths and it's made it a pretty clear choice. It's only about a £35 difference (but I figured that would be £35 I could spend on 2 boxes of film!), and I've calculated that if I shoot 4 rolls of film per month, then the reduced processing time of the 38 degree temp will save me a little under 9 hours per year sat waiting!

I think I can build my tank for around the £100 mark, which is the price of ten rolls of film developed and scanned at UKFL, so it should pay for itself in a few months! :D
 
Carl Hall said:
Thanks for all the replies everyone :) I think I'm going to end up going for the proper Novatronic heater. Chances are that I'd be perfectly ok at the lower temp and not see any noticeable difference (by my untrained eye at least), but it's one less variable to have to contend with!

Just done some quick maths and it's made it a pretty clear choice. It's only about a £35 difference (but I figured that would be £35 I could spend on 2 boxes of film!), and I've calculated that if I shoot 4 rolls of film per month, then the reduced processing time of the 38 degree temp will save me a little under 9 hours per year sat waiting!

I think I can build my tank for around the £100 mark, which is the price of ten rolls of film developed and scanned at UKFL, so it should pay for itself in a few months! :D
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Sounds like a good plan.

I for one would be very interested in seeing how you get on and more details about the heater you're using etc. My old CPP2 is still chugging along, but I know it's going to die one day and be uneconomic to repair. I may then be in the market for an aquarium heater :-)
 
I'll probably put a thread up when I do it, but it's nothing very technical or complicated :) I just basically plan to use an Novatronic heater (which is basically an aquarium heater with a higher maximum temperature) and small aquarium pump to heat a 20L plastic box filled with water, and have bottle and dev tank holders fastened to the inside to stop all the bottles bobbing about. Nothing exactly new or exciting, but hopefully will make it a bit easier lol
 
I shall follow with interest as at the moment I'm using a washing up bowl which does not retain heat very well and isn't really deep enough.
 
Andysnap said:
I shall follow with interest as at the moment I'm using a washing up bowl which does not retain heat very well and isn't really deep enough.
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ChrisR said:
Carl, I hope you're going to do a maker thread, following on from @stevelmx5 's excellent example!

You might also be interested in this thread on the black and white forum: http://www.digitalmonochromeforum.co.uk/threads/processing-film-cut-out-the-hassle.856/
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Oh dear, I should have kept my mouth shut... I could have failed then and no one would have known :D Now there's pressure!
 
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