Caffenol-19: A High-Contrast Coffee-Vitamin C Developer
A project to perfect the use of coffee and vitamin c as a developer that is both effective and non-toxic

This project had its informal start with the Handmade Film Institute's Jamaican Film Workshop, in March of 2010. We wanted to use something that was A) non-toxic, and therefore not a problem to dispose of or to carry across an international border, and B) made of things that could be purchased at a local store, just in case the border crossing proved an issue.

The first thought was to use just Vitamin C (Ascorbate), but I could never get it to work well alone. In thinking about grocery store developers, however, coffee came to mind. That it works as a developer has been well reported, and many have verified it. But it doesn't work especially well, either. But how about together with Vitamin C? Could they work superadditively, like Hydroquinone and Metol? The actual develping agents in coffee have not been identified, and it's certainly possible. After some trials and surveys of published work with Ascorbate, I came up with a formula that seems to work reliably and reproducibly. The only major issue is that it's a "staining" developer, and that issue needs to be addressed, but it's certainly not a fatal flaw.

All the negative processing we did in Jamaica was done there in a cave on the beach using a developer made from local Blue Mountain coffee and Sodium Ascorbate. The results were impressive, more or less as good as if we had used a conventional black and white negative developer like D-76 or D-96. But the setting was a bit rough, so the question remains: how good is it in a real darkroom setting, and will it really hold its own against the old stand-bys?

Based on this initially positive result, and on subsequent successes, it seems clear that there is real potential in this formulation, not just in the novelty that it works at all, but to be a relibale developer that can replace standard formulations without compromising the quality of the film. With this in mind, the current research project is to refine the formulation so as to make it as good as it can be, and to see just how good that is.

For the moment, here is the initial recipe, given in rather loose (but still effective) volume measures.

 Kitchen MeasurePrecise Measure
Coffee (ground)1 lb44 g/l
Sodium Ascorbate*8 oz (1/2 lb)28.375 g/l
Sodium Carbonate (Arm and Hammer Super Washing Soda)1 cup30 g/l
Water2 US gallons1 liter
*Note: Ascorbic Acid can probably be used, and it's cheaper and certainly easier to find, but you may need to add more Washing Soda (or a few spoonfuls of Red Devil Lye, also a grocery store item) to keep the pH at 10.5+, which is what it ought to be. But it might work as a substitute without any other modifications.
*Also Note: the "precise" measures are the ones actually used to develop the formula, and deviate from the "kitchen" measures. The kitchen measures were meant to be easy to make in the field, and have been verified to work empirically!

For a whole batch, brew the coffee in 2 gallons of boiling water (tap water is fine). We brewed the coffee "cowboy style," just adding the ground coffee to 2 gallons of boiling water, removing it from the heat, then letting it sit for about 15 minutes. The subtleties of brewing for best development definitely needs to be refined! After 15 minutes, filter out the coffee grounds with something like a cheesecloth-lined funnel. In Jamaica, we used he burlap bag that the coffee came in!

Add the Carbonate (Washing Soda) to the still hot coffee, and stir to disolve. It won't be any good to drink after this, if it ever was!

Let the coffee cool to something like a working temperature (27C was what we used, as that was about the ambient temperature outdoors at night in the Caribbean). Add the Sodium Ascorbate and stir to disolve.

You're ready to process! 2 gallons is a good volume for processing 100 feet of film in buckets (see our Notes on Bucket Processing). Process (in a bucket -- times for other methods may vary) for 5 minutes @27C. Rinse, and use any fixer (onions?) and Hypoclear (if you use a conventional Thiosuphate fixer). Wash for 5 - 10 minutes in running water (in Jamaica, we left it in a tidepool for an hour), and hang to dry.

More refinements will be forthcoming. We welcome anyone who would like to participate to join us. If you would like to be a part of this project, please email us at

This project has now moved to the Handmade Film Research website, where it a "Current Research Project" at www.handmadefilm.org/research under "Coffee Ascorbate"