Does Caffenol expire, or can it be stored?

Its been said that the Caffenol ingredients can´t be diluted in water prior to use, as they will rather quickly loose their effectiveness. As with most things, at least according to my experience, this depends. If you are happy with your solutions still working 6 weeks after dilution, then yes, solutions can be premixed. By this I mean mixing with water as to be ready for mixing when developing, negating the need to measure up and dissolve powders when the time comes to develop a film. It also helps reduce measuring inaccuracies, as you will be operating with much larger amounts of the different components.

There are three main ingredients to Caffenol-C-H and C-M. Sodium Carbonate, Coffee and ascorbic acid. C-C-H may need a dash of Potassium Bromide, I´ll come to that later.

My Paterson 4 tank takes 500ml of developer for a 120 film. I therefore want to measure up three equal parts, volume, to make up the developer. This means that each premix solution needs to be 3x more concentrated before mixing. I take three two-litre compressible stand bottles such:

Sodium Carbonate: 3x54 grams pr litre (162g/l), two litres = 324g/2l
Ascorbic acid 3x16 grams pr litre (48g/l), two litres = 96g/2l
Coffee (instant) 3x40 grams pr litre (120g/l), two litres = 240g/2l

This will result in 6 litres of developer, enough for 12 shots of 500ml (1/2l) in a Paterson 4 tank

If you need Potassium Bromide, premix it to a concentration of 1g/10ml and add between 2.5 and 10ml (0.5g - 2g/l) to the mix if needed. Faster films typically need more, slower films may even do without.

I´ve done this. Apart from the advantages listed above, you will be able to start development much quicker as all you need to do is mix the solutions together and use more or less immediately. You need not wait for the powders to dissolve and the solutions to settle. I mix the carbonate and ascorbic acid first, then add the coffee last.

Does it work? Well all the films from the previous blog entries here have been developed from the same premixed solutions. A few examples from last film I developed can be seen below. At the time of developing the solutions had been stored for over 6 weeks!

Kowa Super 66, Kowa 85f2.8, TMAX100, EI 80, Caffenol-C-H, 16min@20C

Kowa Super 66, Kowa 85f2.8, TMAX100, EI 80, Caffenol-C-H, 16min@20C

Kowa Super 66, Kowa 85f2.8, TMAX100, EI 80, Caffenol-C-H, 16min@20C

Kowa Super 66, Kowa 85f2.8, TMAX100, EI 80, Caffenol-C-H, 16min@20C

Back to TMAX100 in Caffenol-C-H

This seems to be a trustworthy and safe bet, every time. I´ve now landed on a Caffenol-C-H derivative which follows the standard recipe to a T, apart from a reduced level of potassium bromide; 0.4g/l. This roll was exposed under very different conditions. From afternoon sun, cloudy conditions, to night long exposure scenes. All came out very nicely.

TMAX100 in Caffenol-C-H* @20C/68F 16 minutes

In the woods just before sundown (enlarge to see it in detail):

Kowa Super 66 w/85f2.8 TMX EI 80

Night shots:

Kowa Super 66 w/85f2.8 TMX EI 80 (reciprocity corrected 32s metered, 65s exposure, 1/8th GN48 flash pointed skywards to illuminate weather vane)

Kowa Super 66 w/85f2.8 TMX EI 80 (reciprocity corrected 35s metered, 75s exposure)

Caffenol-C-H took all in its stride. TMAX100 and C-C-H is a bullett proof combination.

Caffenol-C-H second test roll TMY-2

Second roll of TMAX400. This time upped the potassium bromide to the Caffenol.blogspot.com recommended base level. TMAX100 seems to require no bromide at all to keep the haze in check, TMAX400 however is another matter. Even with 1g/l this second go wasn´t without quite a bit of haze, though better than the first effort. Made for an easier time in post-processing. When I next get hold of TMAX400, I´ll be upping the bromide a bit more, and adding somewhat to the development times as it to a certain degree arrests development.

Autumn at its dreariest does have its own allure. Kowa Super 66 w/85mmf2.8, TMAX400 EI 320, Caffenol-C-H @ 13m45s 20C:

Kowa Super 66 w/85mmf2.8 @f11, TMAX400 EI 320, Caffenol-C-H @ 13m45s 20C

Caffenol-C-H first test roll TMY-2

After, at least my my standards, finding a successful recipe for TMAX 100, I thought I´d have a go at TMAX 400 (TMY-2). This seems to be a different emulsion altogether. I looked up whatever I could find on TMY-2 in Caffenol. The caffenol blogspot had some examples of course, but these were done in Caffenol-C-L, not C-H. Stand development, and not agitated etc. So were to start? Well I took the same solution as before, C-C-H with reduced potassium bromide levels, and my experience with development times TMAX 100 and guessed at 15 minutes @ 20C. I shot a roll of 120 film at EI 200, 400, 800 and 1600. Something or other didn´t quite fit. Exposures EI 200 to 800 more or less came out equal. Flat, rather flatter than TMAX 100. The negatives also displayed a lot more haze than with TMAX 100 (were haze is practically non-existent). The results don´t really merit being put up here, apart from one shot which came out rather nicely. At least the whole roll wasn´t a disaster:

TMY-2 EI 800 in Caffenol-C-H 0.4g/l potassium bromide 15min @ 20C

Looking at the negatives I wouldn´t say they were underdeveloped. I will develop my next roll with 1g/l of bromide and see how that goes. I´ll reduce the development time a couple of minutes too.