Caffenol/C shelf life?

[grommi]

Hello,

first let me thankk anybody for the warm welcome here and the big interest for my blog and the feedback.

I'm often asked if Caffenol/CaffenolC can be mixed in big quantities (f.e. 5 litres) and stored. I read mostly that one should use it immediately, but sometimes I came across people saying it works.

Does someone have reliable experiance with storing ready mixed Caffenol/C?

Thanks a lot - Reinhold

 

[Toffle]

My experience with printing using Caffenol (with and without "C") is that it rapidly loses potency and yeilds low density/low contrast prints. Granted, I have not tried either often enough to quantify my results, but from my first experiences, there seemed little point in wasting more paper. The basic recipe is so easy to mix anyway. I generally keep a batch of the dry ingredients ready to go. All I have to do is add water, mix and print.

Nice work on your Caffenol negs, by the way.

Cheers,

 

[ntenny]

One of the projects I may never get around to is what might be called "CC-TEA": a version of Caffenol C with everything dissolved in triethanolamine (TEA) rather than in water, stored as a concentrate to be diluted at time of use, a la PC-TEA. The organic solvent is certainly highly effective at keeping phenidone from oxidising and losing potency over the long haul; I'm curious whether it would have the same benefit for the developing agent in coffee.

But I don't even know if instant coffee will dissolve in TEA. Still and all, it seems like such an opportunity for bad puns that I hope someone tries it out.

-NT

 

[Athiril]

Why do you need to keep a solution.. the chems last forever in the packets/cans


In any case, you could probably extract the caffeic acid from the coffee with denatured alcohol and evaporate it.

 

[removed account4]

i have often thought of mixing a HUGE batch of caffenol C - dry ingredients so i can just measure out some
and mix with water, but since the ingredients are different weights i worried the heavy stuff would always
sink to the bottom and nothing would be dispersed.

i have mixed a stock solution and then used and replenished it with fresh developer
as i would with any other developer i use for film. it worked fine from what i remember, no problems ...
but it wasn't stored for any length of time. it might have stayed fresh since i mix stock print developer in there
ansco 130 lasts for a long long time, even in open trays ... so who knows.

 

[gainer]

If you try either TEA or propylene glycol as solvent, remember that carbonate is not soluble in either. TEA may provide the necessary pH when diluted to working strength. A glycol solution will require a separate alkaline solution, for which the formula used with the Pyrocat series should work quite well.

Heating will be required while dissolving the coffee and C if you want it to happen in your lifetime, as there is little or no molecular motion at room temperature in these organic solvents. A double boiler will keep the temperature within safe and useful limits.