Caffenol - Temp Drift & Cold Start

[Alan9940]

I'm developing 4x5 film in a Paterson System 4 tank with Caffenol CL(CS) doing a cold start at 59F, stand development. How concerned should I be about temperature drift? Currently, the ambient temp in my darkroom is about 66F and after 10 mins of stand development, the coffee mixture was 61F. During the summer months (which is much of the year where I live), the ambient temp in the darkroom hovers around 82F. It seems logical that the caffenol temp over the course of a stand development duration will rise faster and to a warmer temp during the hot months of the year. During the hot months, should I use a water bath to keep the caffenol temp close to what I'm seeing now?

 

[fs999]

I use a water bath with a Sansaire sous vide machine to maintain the temperature (when it's colder) and increase 1°C (33.8°F) every 12 minutes for a 60 minutes development (60/(20°C-15°C=5)).
In summer times I add ice cubes when water begins to heat too fast. This summer we had an heat wave and I could not do CLCS so I developed in CL with a lot of ice cubes
I don't understand why there is no water heater and cooler on the market...

 

[FotoD]

I wonder what the temperature is at floor level during the summer? It can make quite a difference, but it's probably still to warm in Arizona.

Or some low-tech insulation around the tank might do the trick?

 

[fs999]

Or some low-tech insulation around the tank might do the trick?

Yes in a thermos jug, if you find one large enough

 

[Alan9940]

Yes, I thought of using a water bath but was just curious if temp drift when doing Caffenol stand development would be similar to using any standard formula. For example, if I cold start at 59F and the Caffenol temp rises 2-3 degrees over 10 mins, and I'm pleased with the resulting negatives, should I maintain a water bath around 62F during the hot months? Or is Caffenol not as affected by temp? The temp could rise 10 degrees with little effect?

 

[fs999]

Caffenol is less affected, but with cold start the temperature must rise regularly, else it doesn't make sense to do it. With CL temp can be between 18 and 22°C (65-71°F)

 

[Alan9940]

Caffenol is less affected, but with cold start the temperature must rise regularly, else it doesn't make sense to do it. With CL temp can be between 18 and 22°C (65-71°F)

Thank you.

 

[Randy Stewart]

I doubt you will get any well researched answer to your question. In part this is because there are so many variables in making "caffenol", that it's hard to set any standard for its use. Another is that the "process to completion" nature of stand development (which I took to be your process) tends to even out process variables over the "stand" period. I suggest that you just do the experiment yourself Assuming stand development with a highly diluted developer, over an hour or so, I doubt temperature or it variations will make much difference so long has you can keep things in the range of 68 to 85 F. Much below 68F, you will have significant activity change in the developing agent; above 85F, you may soften the film emulsion enough for it to be easily damaged.

 

[nosmok]

In sunny SoCal, not quite so hot as AZ, I run a big bucket of water in the sink from which I take all the H2O I use for making my Caffenol solution and all the rinses. I add ice or heat up some in the microwave as needed. Doing some stand (mostly semi-stand, I guess), I can't say I have worried about the temperature shift DURING processing-- I imagine it's 'baked in', so to speak, along with the temperature rise from the sodium carbonate, etc. When I'm doing LOW-TEMP stand developing for age fog reduction, I have worried more about it, but again there's only so much I can do with the current facts of my life (aka developing in the kitchen).

I have seen people on this forum speak of basically 'inverting' the temp rise problem , by doing stand dev in the refrigerator. You might be able to try that-- my fridge is too full.

 

[Alan9940]

I've decided I'm going to keep doing the cold start stand processing (seems to really work well with this old HP5 I have), and then do some testing when the warm months roll back around. I probably will maintain a water bath to keep the temp from rising above 68F, so it will be interesting to see how much affect (if any) the rise from 59 - 68F has. No doubt I'll be done shooting off this old film by summer and will probably return to normal caffenol processing with fresh HP5.

 

[fs999]

When I'm doing LOW-TEMP stand developing for age fog reduction, I have worried more about it, but again there's only so much I can do with the current facts of my life (aka developing in the kitchen).

I use 1-2 gr per litre of Kbr (potassium bromide), it helps a lot in full stand, even with low speed films (100 ISO), it clears up the negs. Iodized, or not iodized, salt are far less effective. as you can see here :

I've decided I'm going to keep doing the cold start stand processing (seems to really work well with this old HP5 I have), and then do some testing when the warm months roll back around. I probably will maintain a water bath to keep the temp from rising above 68F, so it will be interesting to see how much affect (if any) the rise from 59 - 68F has. No doubt I'll be done shooting off this old film by summer and will probably return to normal caffenol processing with fresh HP5.

One other thing you must keep in mide : less you agitate, less the grain is apparent. That's why I have changed the 1 minute gentle agitation (seen on some sites) to 10 slow inversions as stated in The Caffenol CookBook & Bible.

 

[Alan9940]

One other thing you must keep in mide : less you agitate, less the grain is apparent. That's why I have changed the 1 minute gentle agitation (seen on some sites) to 10 slow inversions as stated in The Caffenol CookBook & Bible.

That's what I do, too...10 slow and gentle agitations initially, then the tank sits until the end.