Caffenol Experiment 1

This blog entry opens up a series of blogs I’ll write as part of my “Light Chasers” project. Today, I discuss my initial experiment in developing film with coffee.

The practice of developing black and white film with coffee (“caffenol”, as it is known colloquially) is well-described. There is a group of caffenol aficionados on Facebook (click here), on Flicker (click here), and there is a full website dedicated to the subject (click here).

I first ran my own experiment with caffenol back in February of 2012. I am including a series of caffenol-developed images as part of my Light Chasers project.

I shot some black and white film back in August of 2018 while I was on vacation in Brainerd. It sat undeveloped until yesterday, when I “went to the laboratory” (i.e., laundry room) and set up my first new attempt in over six years.

I started with a roll of Kentmere 100 35mm film, shot in my Olympus OM1-n camera that I bought in 1979 with my high school graduation money. I don’t have a dark room, so I load the film onto the developing reel inside a “dark bag”. Once on the reel, the film goes into the developing canister, where it is sealed away from light, but the developing chemicals can be poured in and dumped out.

I used my own variation of a standard “caffenol-C” recipe to create the developing fluid. In my case, I used regular coffee grounds (Folgers, I think), 4 tbsps to make 12 cups of coffee in a standard coffee maker.


This recipe calls for 24g of washing soda (I used a fresh box of Arm and Hammer, bought at the grocery store), and 20g of Vitamin C. The soda and vitamin C moderate the pH of the caffenol to keep it above pH 7.  I used vitamin C capsules with rose hips (not recommended, by the way). I dissolved each in about 75 mL of hot water. The vitamin C capsules are troublesome because they contain waxes and fillers that make a gummy mess, and you don’t want that covering your film. I’ll explain how I addressed that problem.

Double Pan Balance
Double Pan Balance

I had hoped I could use a clean paper coffee filter to filter off the gummy residues from the vitamin C capsules, but the gumminess quickly clogged the pores of the filter paper and nothing else would pass through. When I poured the vitamin C liquid directly into my dissolved washing soda, the gummy stuff “curdled” (chemists call this “flocculation”), and I was then able to pass it through a filter, and clear liquid came through, which then became part of the final caffenol recipe. It was a lot of extra work (this is why pure vitamin C powder is preferred over capsules), but as you’ll see, it paid off.

I prepared my caffenol (750 mL of the brewed coffee, cooled to 70 degrees Fahrenheit, with the clarified washing soda/vitamin C solution added), and was ready to begin. I began with a short pre-soak of plain water, which is poured into the developing canister, and allowed to wet the film for about a minute. This is not a standard practice, but I like to do it. I feel it makes the film “receptive” to the chemical developer. I poured out the water, then added the caffenol. Based on developing charts posted on the website, I estimated I needed 11 minutes of developing time. My film type was not specifically listed, so I had to choose the best match from the list of available films. I agitated the film spool for one full minute, then alternated 30-second intervals of letting the spool stand with 30-second intervals of agitation.

At the conclusion of 11 minutes, I poured out the caffenol, reserving it since I am sure it has more developing capability. I did one short rinse with plain water to remove more of the residual coffee, and discarded the rinse.

Next came the stop bath, which arrests the silver development process. I used standard Kodak stop bath (acetic acid, which most of us know in its diluted form as vinegar). I agitated the spool for about 1 minute in the stop bath. I poured the stop bath and and reserved it, as it can be used repeatedly. The acidic nature of the stop bath inhibits further development of silver in the film.

I rinsed one more time with plain water (again, not necessary according to most recipes, but I like to do it), and proceeded with the Fixer bath. I used Kodafix, diluted to the standard degree (one part concentrate, three parts water), agitating for five seconds at 30-second intervals, for a total fix time of 5 minutes. I poured out the fixer and reserved it, as it also can be re-used.

Next up was an extended rinse (10-20 flushes of the canister with water). At this point the film is developed and can be exposed to light. This is the moment of truth for photographers, because there’s no assurance that the images developed properly in the film. After a quick dunk into a PhotoFlo bath (a wetting agent to minimize water spots on the film as it dries), I took the film out of the tank and removed it from the spool. My heart sank a little as the first thing I saw appeared to be totally blackened film with no images. However, this was the film leader only, and once I extended the film I saw clear and distinct negative images. Success!

I gave the film some time to dry before scanning on my flatbed scanner. I was delighted, though, that my first developing attempt in over six years turned out, especially since I was not strictly following the prescribed caffenol recipes.

I wasn’t even sure what images were on the film when I put it into the tank, so part of the surprise is seeing what the pictures were. I recognized them as images from our Brainerd trip. Here are a few examples of the 24 images on the film roll. You can click on them to get a better look.

My assessment is that these images are less “grainy” than I was expecting, which is a good thing, but also less “contrasty” than I might have hoped, which is a bad thing. I can fiddle with the images electronically at this point to give them the final appearance that appeals to me, but my goal is to get them as good as I can on the actual negative, rather than relying on the computer to fix them afterward.

I have several more exposed rolls to develop, so I will start modifying my process one variable at a time, until I hone in on a process that gives me the results I like, matched to a given film type. Documenting these experiments and reporting the results to the various caffenol online communities is one of the objectives of my grant project.

Watch for more caffenol experiments and their results in future blog posts.


This activity is made possible by the voters of Minnesota through a grant from the Southeastern Minnesota Arts Council thanks to a legislative appropriation from the arts & cultural heritage fund.

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