Caffenol is a film developer made from instant coffee, washing soda, and vitamin C. It sounds like a chemistry experiment gone wrong, but it actually works — and works well. Beyond the novelty, caffenol teaches you how developers actually function and proves that film processing doesn't require exotic chemicals.
Active time: 30-40 minutes Total time: 2-3 hours (including drying)
Familiarity with standard film development is recommended:
- Work in a well-ventilated area—even household chemicals benefit from good airflow
- Avoid inhaling washing soda dust when measuring, and keep it out of your eyes (sodium carbonate causes serious eye irritation)
- Wear gloves when handling the mixed solution
- Never eat or drink in your workspace
- Standard fixer is still required and should be disposed of properly
What is Caffenol?
Caffenol uses three household ingredients that happen to fulfil the requirements of a photographic developer:
- Instant coffee — Contains caffeic acid, which acts as a developing agent
- Washing soda (sodium carbonate) — Provides the alkaline environment developers need
- Vitamin C (ascorbic acid) — Supercharges the development and improves results
The name is a play on coffee. Caffeine itself does not develop film; the active compounds are caffeic acid and related polyphenols.
Why Use Caffenol?
Educational Value
Caffenol demystifies development. Understanding that coffee develops film helps you grasp what's actually happening in any developer:
- Developing agents reduce exposed silver halides to metallic silver
- Alkali activates the developing agents
- The process is chemistry, not magic
Accessibility
You can make caffenol from supermarket ingredients:
- No photo shop required
- Useful in remote locations
- Much cheaper than commercial developers
- Fewer hazardous ingredients than most commercial developers (you still need fixer, which must be disposed of in line with local regulations)
Environmental Considerations
Caffenol is arguably more environmentally friendly:
- Biodegradable ingredients
- No heavy metals in the developer
- Dispose of used developer in line with local regulations
Distinctive Results
Caffenol produces its own aesthetic:
- Moderate grain, good tonal range
- Slightly warm image tone
- Works well with many films
Caffenol was first worked out in 1995 by Dr Scott Williams's photographic chemistry class at Rochester Institute of Technology, and spread online in the 2000s. Photographers such as Reinhold G (caffenol.blogspot.com) have since refined and published recipes, making it a well-documented alternative process.
The Chemistry Behind It
Understanding why caffenol works:
Caffeic Acid (from coffee)
Coffee contains caffeic acid and other polyphenols that can reduce silver halides. It's weaker than traditional developing agents but effective with enough time and alkalinity.
Sodium Carbonate (washing soda)
Developers need an alkaline environment (high pH) to work. Washing soda provides this, typically creating a pH around 10-11. The more washing soda, the more active (and contrasty) the development.
Ascorbic Acid (vitamin C)
Vitamin C is itself a developing agent (used in some commercial developers). In caffenol, it:
- Speeds up development significantly
- Improves shadow detail
- Shortens development time considerably
Caffenol Recipes
The best-documented recipes are Reinhold G's, published on caffenol.blogspot.com. Amounts below are per 500ml of water and assume anhydrous (powdered) washing soda; see the note on soda crystals below.
Caffenol-C-M (Standard Recipe)
The most common starting point, for slow and medium-speed films:
| Ingredient | Amount | Notes |
|---|---|---|
| Instant coffee | 20g | Cheap instant, not freeze-dried |
| Washing soda (anhydrous) | 27g | Sodium carbonate (NOT baking soda) |
| Vitamin C | 8g | Ascorbic acid powder |
| Water | 500ml | Room temperature |
Development time: 15 minutes at 20°C for ISO 100 film (Reinhold's figure); test for other films
Caffenol-C-H (for faster films)
The same recipe with a restrainer added to hold down fog on faster films:
| Ingredient | Amount | Notes |
|---|---|---|
| Instant coffee | 20g | |
| Washing soda (anhydrous) | 27g | |
| Vitamin C | 8g | |
| Potassium bromide | 0.5g | Restrainer (1g per litre) |
| Water | 500ml |
Development time: test from about 15 minutes at 20°C; Reinhold publishes film-specific times on his blog
Other variants
Reinhold also publishes reduced-soda versions ("RS", with 40g of soda per litre instead of 54g) and Caffenol-C-L for long or semi-stand development. Check the blog for current amounts and times rather than improvising.
Use washing soda (sodium carbonate), NOT baking soda (sodium bicarbonate). They are different chemicals. Baking soda won't provide enough alkalinity.
Mixing Caffenol
Ingredients to Source
Instant coffee:
- Cheapest supermarket brand works fine
- Avoid flavoured varieties
- Granules or powder both work
- NOT filter coffee, espresso, or beans
Washing soda:
- Found in laundry aisle
- "Soda crystals" in the UK are the hydrated form: use about 2.7 times the weight given above
- Can be made by baking baking soda at 200°C for 1 hour
- NOT baking soda, borax, or caustic soda
Vitamin C:
- Pure ascorbic acid powder from health food shops
- Tablets crushed finely can work but may contain binders
- Sodium ascorbate also works
Mixing Procedure
Measure 500ml of water at room temperature (20°C).
Add washing soda first. Stir until completely dissolved. This takes a minute or two.
Add vitamin C. Stir until dissolved and wait for the fizzing to stop.
Add instant coffee last. Stir thoroughly until dissolved. The mixture will look like strong coffee. Dissolving the soda warms the water by about 3°C, so check it is back to 20°C.
Let the mixture settle for 2-3 minutes before using. Some foam is normal.
Mix caffenol immediately before use. It oxidises quickly and loses potency. Don't try to store it for later.
The Development Process
Pre-soak (recommended): Fill tank with 20°C water for 2-3 minutes. This removes the anti-halation layer and helps even development. The water will turn blue/purple from the dye.
Pour in caffenol: Start your timer immediately.
Agitate: Continuous agitation for the first 30 seconds, then 3 inversions every minute thereafter.
Development time: 15 minutes for Caffenol-C-M at 20°C with ISO 100 film. Adjust based on your film, recipe and desired contrast.
Stop bath: Water is fine. Rinse 3-4 times.
Fix: Use standard fixer (Ilford Rapid Fix, etc.). Caffenol doesn't fix — you need commercial fixer.
Wash and dry: Standard procedure.
Film Recommendations
Caffenol works with many black and white films, but results vary. Reinhold G tested Caffenol-C-M mainly on ISO 100 films (T-Max 100 and Fomapan 100) and does not recommend it for ISO 400 films or faster; for those, use a variant such as Caffenol-C-H and test first. The lists below are community experience, not maker data:
Excellent Results
- Fomapan 400 — Budget film, handles caffenol well
- Ilford HP5+ — Classic combination, forgiving
- Kodak Tri-X — Good results, slightly more grain than standard developers
Good Results
- Ilford FP4+ — Works well, may need slightly longer times
- Ilford Delta 100/400 — Modern emulsions work but designed for standard developers
- Kentmere 400 — Budget-friendly option
Variable Results
- Kodak T-Max films — Designed for specific developers, results may be inconsistent
- Ilford Pan F — Can work but slower films need longer times
For your first caffenol experiments, a slower, forgiving film such as Fomapan 100 (one of Reinhold's tested films) is the safest start. Keep notes, because results vary between recipes and films.
Troubleshooting
Negatives Too Thin (Underdeveloped)
- Extend development time
- Ensure water is at 20°C (colder water slows development)
- Check that washing soda fully dissolved
- Use more vitamin C for extra developing power
Negatives Too Dense (Overdeveloped)
- Reduce development time
- Reduce agitation
- Try a reduced-soda (RS) variant
Uneven Development / Streaks
- Pre-soak to remove anti-halation layer
- Improve agitation consistency
- Ensure coffee fully dissolved before use
Brown Staining
- Extend final wash time
- Some staining is normal and doesn't affect image quality
- Usually fades with thorough washing
Excessive Grain
- Expected with caffenol — it's a moderately grainy developer
- Use finer-grain films (FP4+, Delta 100) if grain is a concern
- Slight overexposure can help
Stand Development with Caffenol
Caffenol works well with stand development:
Use a recipe published for stand or semi-stand use, such as one of Reinhold's Caffenol-C-L variants with a little potassium bromide added to restrain fog, rather than simply cutting the vitamin C.
Pour into tank and agitate for first 30 seconds only.
Leave completely still for 60-90 minutes.
Optional: one gentle agitation at the halfway point.
Stop, fix, and wash as normal.
Stand development with caffenol gives a strong compensating effect, useful for high-contrast scenes, but as with any stand method watch for uneven development and bromide drag.
Beyond the Novelty
Caffenol isn't just a party trick. Photographers use it seriously because:
- It works reliably — Thousands of documented successful developments
- Results are good — Not just "acceptable" but genuinely usable negatives
- It teaches fundamentals — Understanding caffenol means understanding all developers
- It's accessible — The developer uses supermarket ingredients (though you still need fixer, and used fixer must be disposed of properly)
Once you've developed a roll with coffee, you'll never look at a bottle of D-76 the same way. You'll understand that developers are just chemicals that reduce silver — and those chemicals can come from surprising places.
Keep notes on your caffenol experiments. Small variations in coffee brand, water hardness, or temperature can affect results. Recording what works helps you refine your personal process.
Additional Resources
The caffenol community has documented extensive variations and experiments:
- Wine developers — Red wine with washing soda and vitamin C, shown on photographic paper at caffenol.org
- Herb developers — Various plant-based developing agents
- Beer developers — Beer with soda and vitamin C, also shown on paper at caffenol.org
Caffenol is a gateway to understanding that film development is fundamentally about chemistry, and that chemistry is more flexible than commercial products might suggest.
Sources
- Sodium carbonate: substance information, ECHA
- Caffenol-C-M recipe, Reinhold G, caffenol.blogspot.com
- Soda: myth and truth, Reinhold G, caffenol.blogspot.com
- The RS and RSA variants, Reinhold G, caffenol.blogspot.com
- Dr Scott Williams and the Technical Photographic Chemistry 1995 class (archived), Rochester Institute of Technology
- C&L Inventory (sodium carbonate, potassium bromide), ECHA