Michael just offered a suggestion on Flickr:
".........I think metaborate (a.k.a. Kodalk)
is a more suitable non-carbonate alkali ( than borax) as it has much lower molar mass, much higher solubility, can hit a higher pH, and still have relatively good buffering characteristics. 1g metaborate = 0.692g borax + 0.145g sodium hydroxide if you're interested.
On a slight tangent, I did have an experiment in mind that is somewhat related to this but I have not had time to try so I'll share it here. My goal was to create a longer lasting two part Caffenol-C developer. I was thinking of mixing coffee + vit-c in a very concentrated solution (as little water as possible) with enough hydroxide to make it neutral (this is part A). Part B would be a suitable alkali solution (borax, metaborate, carbonate) with potassium bromide if necessary. My thinking for part A is that the solution might last longer due to the high concentration of ingredients, the vit-c being in sodium ascorbate form, and the pH being neutral. Part B would not have to work so hard as part A is already neutral.
Another possible permutation is to mix part A with alcohol (methanol, isopropyl, etc.) instead of water to minimize oxidation but I have absolutely no idea if coffee + vit-c is soluble in alcohol. "
Lets give this a spin! I will ponder a bit upon this, hopefully Michael will be back with more inputs, and even more welcome, others might offer comments too, I think this is a good idea, and a possible alternative to now out-of-production Daiafine. A two part developer with an extremely long shelf life, little if any time and temperature dependency is nice.
Comment from Michael :
"Haha ... I didn't expect to find this here ... cool.
Anyway, I'm pretty sure we cannot get this to work as a conventional two-part developer such as Diafine or divided D-76 because we need so much coffee for active development. I think it may work by using x volume of part A + y volume of part B + z volume of water, most likely suitable only for one-shot use.
I think that a Phenidone/Vit-C developer would make a better candidate for a true two-part developer like Diafine as so little developing ingredients are required.
The problem here is oxygen ... it's the oxidation of developing agents that makes them weak. I have a fair amount of experience dealing with this problem as Phenidone has this same issue and a few approaches have been used to address this.
Alcohol (methanol) has been used as it generally has little water, hence little O2. Ethylene Glycol, Propylene Glycol, and Glycerin have also been used as they have no water and no O2.
The potential problem with alcohol or glycol is solubility of the developing agents. Experimentation is required to determine how much coffee can be dissolved in various solvents.
Another idea that came out after alcohol/glycol was to use water but have excess preservative, vit-c in this case. The theory being that the excess ascorbate preserves what's there and it seems to work. These principles have been used and proven, the excess ascorbate one is used in PCB, and the glycol one is used in PCM.
If I were to attempt a Phenidone/C two-part developer I would make part A with an Ascorbic Acid to Phenidone ratio of 80:1 and enough sodium bicarbonate to neutralize the solution.
This could work out roughly as 80g ascorbic acid, 40g sodium bicarbonate, and 1g phenidone in 1L water.
Part B would be a 1% sodium metaborate solution.
The pH will be high enough to get some good development and the buffering should make the chemical reaction last as long as is required to exhaust the Phenidone/C from part A. I would do 3-4 mins agitation in part A and 5-10 mins agitation in part B.
I have absolutely no idea if any of this would actually work but I think it could.
Thank you Michael, I have to put my thinking cap on, will be back with questions.....