Caffenol developer storage-- Another data point.

[nosmok]

For us Caffenol people here on Photrio (there's a few I think): Today I souped a roll of 120 Tmax 100 I shot yesterday, re-using a pint of Caffenol CM I had used on another roll of 120 Tmax 100 back late last November. I put it in a pint plastic water bottle and squeezed all the air out. Before I poured it in the tank, I got it up to 20C, then added a bit of each of the soda, coffee, and ascorbic acid (fractions of a teaspoon, roughly corresponding to the proportions of each in Caf CM). It developed today's roll perfectly! This is the best experience I've had trying to store and re-use Caffenol developer. I think the squeezing the air out is key to getting it to work. Next I'll try the other Caffenol recipes I use. Apologies if this is old hat to the Kaffeic Krew.

 

[Donald Qualls]

I've always considered Caffenol one-shot. There's no preservative except for one of the developing agents (the ascorbate). There's no workable way to know how much of the ascorbate has been used up acting as preservative in storage (or whether Fenton reaction has destroyed all of it due to iron or copper impurities in your washing soda or water).

IMO, you dodged a bullet, possibly largely because of your "replenishment" with fresh ingredients.

 

[Rudeofus]

I've always considered Caffenol one-shot. There's no preservative except for one of the developing agents (the ascorbate). There's no workable way to know how much of the ascorbate has been used up acting as preservative in storage (or whether Fenton reaction has destroyed all of it due to iron or copper impurities in your washing soda or water).

IMO, you dodged a bullet, possibly largely because of your "replenishment" with fresh ingredients.

+1 to that. The reason, why Ascorbic Acid based developers suffer from "sudden death" is, that small amounts of Ascorbic Acid still show development action, and these small amounts can be gone in a very short time frame. By adding a small amount of Ascorbic Acid @nosmok basically revived the developer.

Also: Fenton decomposition speed of Ascorbic Acid can vary widely, especially in such a non-defined environment like Caffenol. Sudden death of XTol happened to people, who were very happy with XTol for many rolls, until one suddenly came out blank.

 

[nosmok]

+1 to that. The reason, why Ascorbic Acid based developers suffer from "sudden death" is, that small amounts of Ascorbic Acid still show development action, and these small amounts can be gone in a very short time frame. By adding a small amount of Ascorbic Acid @nosmok basically revived the developer.

Donald Qualls:
...IMO, you dodged a bullet, possibly largely because of your "replenishment" with fresh ingredients.

Your consensus may well be correct, but it should be noted the additional stuff was less than 2 teaspoons' worth by volume, mixed into 500ml of existing solution (apologies for mixing SI and English units). I think the lack of air in the storage vessel also had an effect-- I never had results this good with this replenishment regime when I was storing 500ml solution for a week or so in a 1liter bottle. I'm not sure if I will trust this stuff for important shots, but I'll probably keep some around for camera or lens tests.

 

[fs999]

Caffenol CM or CH can be reused (someone on the facebook Caffenol page stated he reused three times the CM recipe), but don't try that with the weaker CL variant, it will not work !

 

[relistan]

Donald Qualls:
...IMO, you dodged a bullet, possibly largely because of your "replenishment" with fresh ingredients.

Your consensus may well be correct, but it should be noted the additional stuff was less than 2 teaspoons' worth by volume, mixed into 500ml of existing solution (apologies for mixing SI and English units). I think the lack of air in the storage vessel also had an effect-- I never had results this good with this replenishment regime when I was storing 500ml solution for a week or so in a 1liter bottle. I'm not sure if I will trust this stuff for important shots, but I'll probably keep some around for camera or lens tests.

Keeping air out will help to prevent aerial oxidation. And you might have pretty good luck with it for a long time. But then one day it might not work any more because of the ascorbic acid breaking down. This is what @Donald Qualls and @Rudeofus are talking about. But it turns out that the other constituents of coffee, which are the other developing agent in caffenol, can also die from the same reaction. Replenishing it like you did will definitely help keep it alive, but if I were doing this I would definitely develop a scrap leader each time I got it out to make sure it reaches the expected density in the right time frame. Then you will know it's still probably OK before you ruin a roll.

 

[nosmok]

@Donald Qualls, @Rudeofus, thanks for your responses about the failure modes of Ascorbate developers. This is why I post here-- to find out stuff I don't know about things photographic, and to share the bits I do.

@fs999: "Caffenol CM or CH can be reused (someone on the facebook Caffenol page stated he reused three times the CM recipe), but don't try that with the weaker CL variant, it will not work !" This is my experience too.

@relistan "if I were doing this I would definitely develop a scrap leader each time I got it out to make sure it reaches the expected density in the right time frame. Then you will know it's still probably OK before you ruin a roll." That's basically what I did-- I had the CM solution just hanging around, and had shot a quick 120 roll after one of our many recent rainstorms. I just tried it, figuring I could mix up a fresh batch if my development heuristics showed nothing doing with the old stuff.

 

[eli griggs]

It might just be wiser to keep back some once used Caffenol as a "conditioner" for mixing up new batches of Caffenol Developers, as some darkroom folks do with old Ansco 130 (for example, use two year old stuff or older) for new batches of that developer, which seems to season (or condition) the new batch somewhat for the better.

This way, unless mold or other nasties have grown in old Caffenol, you can keep track of the results and later compare them to always using fresh or the same formulas.

Otherwise, you're just testing how far you can walk the razor's edge, just for the thrill of the fall.

IMO.

 

[Donald Qualls]

FWIW, the reuse cited on the Facebook Caffenol page is probably multiple rolls on a short time frame (same day?), as opposed to treating Caffenol like D-23 or D-76.