Caffenol – Developing Black & White Film with Coffee

What is Caffenol?

Caffenol is an alternative black-and-white film developer made from readily available household ingredients. Instead of conventional photo chemistry, it uses instant coffee, washing soda (sodium carbonate) and often vitamin C (ascorbic acid).

Despite its DIY origins, Caffenol is fully capable of producing consistent, high-quality negatives with a characteristic tonal rendering.

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Why use Caffenol?

• Accessible & low toxicity – ingredients are easy to source worldwide
• Excellent highlight control – long tonal scale, gentle roll-off
• Flexible – works with many classic and modern emulsions
• Distinct look – slightly softer contrast, organic grain structure

Limitations: longer development times, higher sensitivity to temperature, and film-dependent results.

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Ingredients & Function

Ingredient	Function
Instant coffee (not decaf)	Primary developing agent
Washing soda (Na₂CO₃)	Creates alkaline environment
Vitamin C (ascorbic acid)	Accelerates development, improves efficiency
Water	Solvent

⚠️ Baking soda / sodium bicarbonate is not a substitute for washing soda.

Base Recipes (1 Liter)

Caffenol-C-M (Classic, balanced)

• 40 g instant coffee
• 54 g washing soda
• 16 g vitamin C

General time: 12–15 min @ 20 °C (ISO 100–400)

Caffenol-C-L (Low soda, lower contrast)

• 40 g instant coffee
• 30 g washing soda
• 16 g vitamin C

General time: 15–18 min @ 20 °C

Push Processing with Caffenol (ISO 800–1600)

Caffenol can be pushed, but expectations must be realistic: contrast increases, grain becomes more prominent, and shadow detail is limited by the emulsion.

Push strategy

• Increase development time, not temperature
• Keep 20 °C for control
• Slightly reduce agitation to protect highlights

Example Push Times (Caffenol-C-M, 20 °C)

Film	Box ISO	Push ISO	Time
Ilford HP5+	400	800	18 min
Ilford HP5+	400	1600	22–24 min
Agfa APX 100	100	800	20–22 min
Fomapan 100	100	800	22–24 min

ISO 1600 pushes on ISO-100 films are possible but very contrasty and best reserved for experimental work.

Film-Specific Caffenol Recipes & Times

Fomapan 100

Classic cubic-grain film, reacts well to Caffenol.

Recommended recipe: Caffenol-C-M

• ISO 100: 12–13 min @ 20 °C
• ISO 200: 14–15 min
• ISO 400: 17–18 min
• ISO 800 (push): 22–24 min

Look: pronounced grain, strong character, good midtones

Tip: avoid over-agitation to prevent blocked highlights

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Agfa APX 100

High sharpness, slightly harder contrast.

Recommended recipe: Caffenol-C-L

• ISO 100: 13–14 min @ 20 °C
• ISO 200: 15–16 min
• ISO 400: 18–19 min
• ISO 800 (push): 20–22 min

Look: crisp edges, higher micro-contrast

Tip: C-L keeps highlights under control better than C-M

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Ilford HP5+

Very flexible, excellent for push processing.

Recommended recipe: Caffenol-C-M

• ISO 400: 14–15 min @ 20 °C
• ISO 800: 18 min
• ISO 1600: 22–24 min

Look: classic reportage grain, good shadow retention

Tip: extend fixing time slightly due to dense negatives when pushed

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Replacing Potassium Bromide (KBr)

In traditional developers, potassium bromide acts as a restrainer to reduce fog. If KBr is unavailable, these options work in Caffenol:

Practical alternatives

• Iodized table salt: 0.5–1 g / liter
  • mild fog reduction, slight contrast increase
• Potassium iodide (KI): 0.1–0.2 g / liter
  • very effective, dose carefully
• Process control:
  • keep temperature ≤ 20–21 °C
  • avoid excessive development times
  • reduce vitamin C slightly if fog appears

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Stop, Fix & Wash

• Stop bath: plain water (30–60 s)
• Fixer: standard B&W fixer (rapid or sodium thiosulfate)
• Wash: normal washing routine, optional wetting agent

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Conclusion

Caffenol is far more than a curiosity. With accurate mixing and disciplined processing, it delivers reliable, expressive negatives and even supports push processing up to ISO 1600—especially with films like HP5+.

Its combination of accessibility, control, and unique image character makes it a compelling choice for both experimental and serious analog photographers.

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