Developing Film with Coffee - Caffenol

Writing & Photography by Jay Revelle

No matter the location on this planet, a good number of humans start their day with a coffee. Whether a cappuccino, macchiato, Americano, cafe latte, double drip, half-caf double decaf (my favorite), or the dreaded/beloved instant coffee, it’s a process.

Coffee is reported to be capable of many things, like preventing cancer, reducing high blood pressure, mitigating diabetes, etc. It’s great to know that multiple cups a day might actually be good for you. However, if you’re a film photographer, you might want to brew a few extra cups. Coffee—particularly instant coffee—has another use: Developing film. It’s called “Caffenol.”

In 1995, the term “Caffenol” wasn't yet coined. Washing soda (sodium carbonate) was used as the pH-adjusting agent, and since about 2000, vitamin C was added, drastically improving image quality. With that, Caffenol was born.

Caffenol, of course, doesn’t start with me nor does it end in my makeshift home photo lab. I live in Japan, but this story starts in Rochester, New York. In the mid-20th century, Rochester was the epicenter of the American optics industry and was thus enraptured with all things film photographic. It was an era marked by the beauty and romance of film, and was also a heyday of high-quality American manufacturing. Rochester was home to a multitude of famous photography-specific manufacturers, such as Kodak, Graflex, Wollensack, and Bausch & Lomb. Kodak is still based there and George Eastman, Kodak’s founder, lived in a sprawling Rochester mansion, now known as “George Eastman House International Museum of Photography and Film.” With DNA so steeped in film history, it makes sense that Caffenol was born in Rochester.

Unfortunately, the photographic boom of Rochester is no longer. However, if we could travel back, even just to 1995, we could watch history unfold at the Rochester Institute of Technology, where the Technical Photography Class of ‘95, taught by Dr. Scott A. Williams Ph.D, embarked on the novel challenge to devise a film developer formula using only household materials—those that are easy to procure, easy to dispose of, and cheap.

The class exercise first identified selective developer molecules and after intense experimentation involving all sorts of items (ascorbic acid, hydrogen peroxide, soaps), they discovered that the phenolic acids (tannins) and caffeine (caffeic acid) offered the best chance for film development. The official report on the experiment would later cite: “An organic developer is usually built around a ring of carbon atoms called benzene rings. There are usually one or two electron-rich groups of atoms, attached to the ring, which provide the necessary electron to initiate development. One of the oldest of these is hydroquinone, as well as p-phenylenediamine—a common color development agent. The pH of the solution controls the function of the developer in the process.”

Yes, a lot of science can be tied into art, and coffee. Another finding of the report mentions that coffee contains just about every type of molecule known to nature, including proteins, lipids, and carbohydrates. In addition to kick-starting our mornings with caffeine, coffee contains a group of molecules known as phenols, one of which is caffeic acid. This type of phenol is comparable to a molecule of catechol, which is well known as an effective photographic developer. Coffee contains several other phenols that closely resemble other hydroxyl-containing developer agents used in photography, proving that the molecular structure of caffeine is larger than a benzene ring and contains “all of the constituents of an effective developer.”

However, straight coffee is not enough. Acid is not enough. The pH needs to be modified. The gelatin needs to be swelled to allow for the diffusion of the developer to the exposed silver halide grain, where buffers (usually salts) are applied in order to maintain a select pH level. In keeping with the household requirements of non-traditional development, baking soda (sodium bicarbonate) and potassium hydroxide (used to unclog drains), can be used as the buffering components for developing.

The safety and ease of finding the ingredients, combined with the novelty of using coffee, blew my mind. I can drink coffee and develop film from the same pot, then pour the developer down the drain? Amazing!

Caffenol can yield extremely fine-grain negatives from black and white film—quality that rivals the most established processing methods. Caffenol is mainly considered a black and white film developer, but slide and color film result in a unique sepia-toned outcome. It can likely be paired with any film to create results.

Traditional photography using light-sensitive materials is a perfect example of the union of science and art, in real time. Caffenol is the doorway to exploring hands-on film development and there's nothing like developing film at home, with coffee, while drinking coffee.

The enchantment of the era of film photography, embodied in Rochester, New York in the mid-20th century, can still be experienced in a cup of Caffenol. No matter the methods employed, the beauty of film is beckoning. And the same goes for a good cup of coffee. Is it not time for a new romance?

Basic Caffenol Developer Recipe

• 1 liter of tap or distilled water (preferably around 20°C)
• 23 grams of washing soda (sodium carbonate, dry)
• 16 grams of powdered ascorbic acid (vitamin C)
• 44 grams of instant coffee
• Mix ingredients in order until all solids are completely dissolved
• Depending on film ISO, development times and agitation may differ