High quality and fool proof Caffenol developer for black & white films.
After 1 year of caffenol experiments - trying out variuos strenghts, compositions and agitation methods with various black & white negative film, I have now come up with a a favorite mix and method that works really well with my prefered films, Kodak Tri-X, Ilford Delta and Kodak Double XX (5222). Actually, it works GREAT! Here it is, my new favorite Caffenol recipe:
Caffenol, my house recipe
(For 1 liter Caffenol)
100 ml instant coffee (or 1 liter very strong coffee, if you use good stuff)
100 ml crystal soda (crystal soda contains lots of water, so equalivant to apx 35g/40ml waterfree soda)
20 ml C-vitamin
20 ml salt (iodinated). I use iodinated salt as a “restrainer”, to avoid fog on film, instead of the often suggested “potassium bromide”. I refuse to use chemicals that are hazardous!
Temperature of mix should be 20 degrees celcius.
Dev. time: 11-15 min for box speed expossure of 100-400 ISO film, or better, expose your film at real ISO sensitivity.
For “normal” tank development, I agitate all of first minute and then 10 sec. every whole minute.
15 minutes development is tested with great results for these 400 ISO films: Kodak TRI-X, Kodak Double XX (5222), Ilford Delta 400. But I prefer to expose them at 320 ISO.
I disolve the instant coffee in a little boiling water, then I add some cold water (prefably distilled water, but I often use plain tab water) and disolve the crystal soda into the still warm coffee mix. Stir constantly for at apx 3 minutes. Add salt and stir until liquid is totaly free from from any soda or salt crystals. Add C-Vitamin. After stiring to disolve the vitamin, add very cold water (great to have dtistilled water stored in the fridge). Adjust temperature to 20 degrees celcius. You can do this with a water bath of either ice cold water or warm water.
Alternatively to using instant coffee, I often make a very strong coffee of the same kind I normally drink. I make fine coffee powder in a coffee grinder and make either filter coffee, or I brew it in a bistro style pot for 4 minutes and then filter it through an ordinary coffee filter after. For this method, the coffee should make up all your liqued - no extra water. Cool it to 20 degrees celcius before use.
Measure by volume made easy
I use empty film container to meassure the amount I need of both coffee and crystal soda for developing one roll of 35ml film: 25 ml/5 tsp pr. film for 250ml caffenol developer.
Of course you will need enough caffenol to fully cover the film spool in the tank. Usually the volume you need is written on the bottom of the tank, or you can meassure it up yourself.
Some DIY developers (people) believe in more exact meassurement, preferably by weight. But I find that exact meassuring in caffenol making is somewhat misleading. Because the main ingredients used in caffenol aren’t exact in strenght/potency either: Coffee and soda really vary in strenght. You have to “get to know” your own stable of ingredients, and when you know how strong your coffee is and how pure your soda is, and knowing this, you might as well meassure by volume. The “crystal soda” I can buy locally contains so much water, that I need 2,5 times more of this soda than If I had used “waterfree soda” as is listed in most recipies. (I found out by baking the soda I had until it didnt loose any more weight/water).
High image quality - even with high speed films.
Learn from others - and yourself
Like many other Caffenol heads, I refer to and really like the Caffenol Cookbook, but actually this “bible of caffenol” contains many different recipies, so its important to make my (your) own experimentation to find out what strenght, “composition” and developing method is your working caffenol receipe for your choice of films. The Massive Development Chart also lists dev. times for Caffenol development, but does not actually specify the recipe used, and does not give you choises of development method, So I made up my own favority mix by trial and error. The main challenge has been to achieve a dense negative for intense highlights, but avoid a foggy film, with no real clear parts. The result is my “house recipe” (see above) which is weaker (less soda) than the Caffenol CM (rs) reduced soda version, but stronger than Caffenol STD Delta recipe. (You can find both these recipes and more in the Caffenol Handbook.
Following the nomenclature of caffenol recipes, perhaps this version could be called Caffenol CH (srs). “C” stands for C-vitamin, “H” for High Speed films and “(srs)” for “super reduced soda”, since this version contains even less soda than the already named Casffenol CM (rs) recipe.
You can read my first and longer post on DIY Eco film and paper developers here: https://www.peterbjerg.dk/blog/eco