Caffenol-C
An alternative developer using instant coffee as the developing agent, washing soda (sodium carbonate) as the accelerator, and ascorbic acid (vitamin C) as a superadditive developing agent. Caffenol-C demonstrates that photographic development can be achieved with household materials. Results are surprisingly good: moderate grain, reasonable sharpness, and a full tonal range. Development times are longer than conventional developers (12-15 minutes). A popular entry point for DIY darkroom chemistry.
Mixing Instructions
Start with 350 ml of water at 20 °C (room temperature).
- Add instant coffee granules (e.g., 12 heaping teaspoons per liter) and stir until dissolved.
- Add washing soda (sodium carbonate) — approximately 54 g/L — and stir until dissolved.
- Add ascorbic acid (vitamin C powder) — approximately 16 g/L — and stir until dissolved.
The solution will be dark brown and slightly fizzy. Use immediately — Caffenol has no shelf life. Development times are typically 12-15 minutes at 20 °C. Discard after use.
Ingredients for 1L of Working Solution
Volume:
ml
| # | Chemical | Role | Qty (1L) | Unit | Note |
|---|---|---|---|---|---|
| 1 | Sodium Carbonate | Accelerator | 54.0 | g | |
| 2 | Ascorbic Acid | Developing Agent | 16.0 | g | |
| 3 | Instant Coffee | Developing Agent | 40.0 | g | |
| 4 | Potassium Bromide | Restrainer | 1.0 | g |
Process Parameters
Temp:°C
| Film Stock | ISO | Dilution | Temp | Time | Agitation | Source | Notes |
|---|---|---|---|---|---|---|---|
| Fomapan 100 | 100 | stock | 20.0°C | 12:00 | Continuous first 60s, then 10s every 60s | Community data | |
| Ilford HP5+ 400 | 400 | stock | 20.0°C | 14:00 | Continuous first 60s, then 10s every 60s | Community data | |
| Kodak Tri-X 400 | 400 | stock | 20.0°C | 15:00 | Continuous first 60s, then 10s every 60s | Caffenol.org | Results vary with coffee brand. 15 minutes is a good starting point. |