Rodinal
The oldest commercially available photographic developer, dating to 1891.[1] Based on p-aminophenol, Rodinal is a highly concentrated liquid used at extreme dilutions (1:25 to 1:100 or beyond). At high dilutions it produces outstanding sharpness with pronounced edge effects (adjacency/acutance effects) at the cost of visible grain. A favorite for stand and semi-stand development. The grain is sharp and well-defined rather than mushy. Ideal for slow to medium-speed films in medium and large format.
References
- BOOK Modern Photographic Processing, Volume 1 1st ed. John Wiley & Sons, 1979. ISBN 0-471-02228-0. ↩
Mixing Instructions
Rodinal is supplied as a liquid concentrate. Dilute with water at 20°C immediately before use. For 1:25, mix 40ml concentrate per liter of water. For 1:50, mix 20ml per liter. For 1:100 (stand development), mix 10ml per liter. Stir gently after diluting. All dilutions are one-shot — discard after use. For stand development, pour in working solution, agitate gently for 30 seconds, then let stand for 60 minutes with no agitation. The concentrate keeps for years even after opening.
Ingredients for 1L of Concentrate
| # | Chemical | Role | Qty (1L) | Unit | Note |
|---|---|---|---|---|---|
| 1 | p-Aminophenol | Developing Agent | 30.0 | g | (concentrate) |
| 2 | Sodium Sulfite | Preservative | 80.0 | g | (concentrate) |
| 3 | Sodium Hydroxide | Accelerator | 40.0 | g | (concentrate) |
Process Parameters
| Film Stock | ISO | Dilution | Temp | Time | Agitation | Mix (per 1L) | Source | Notes |
|---|---|---|---|---|---|---|---|---|
| Fomapan 100 | 100 | 1:25 | 20.0°C | 6:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Foma Technical Data | Fomapan and Rodinal is a classic pairing. |
| Fomapan 100 | 100 | 1:50 | 20.0°C | 10:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Foma Technical Data | |
| Fomapan 200 | 200 | 1:50 | 20.0°C | 12:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Massive Dev Chart | |
| Fomapan 400 | 400 | 1:25 | 20.0°C | 9:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Massive Dev Chart | |
| Fujifilm Acros II 100 | 100 | 1:50 | 20.0°C | 11:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Massive Dev Chart | |
| Ilford Delta 100 | 100 | 1:25 | 20.0°C | 9:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Massive Dev Chart | T-grain films show less sharpness benefit from Rodinal. |
| Ilford FP4+ 125 | 125 | 1:50 | 20.0°C | 12:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Massive Dev Chart | |
| Ilford FP4+ 125 | 125 | 1:25 | 20.0°C | 7:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Massive Dev Chart | |
| Ilford HP5+ 400 | 400 | 1:50 | 20.0°C | 13:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Massive Dev Chart | |
| Ilford HP5+ 400 | 400 | 1:25 | 20.0°C | 9:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Massive Dev Chart | |
| Kodak Tri-X 400 | 400 | 1:25 | 20.0°C | 11:00 | Continuous first 60s, then 10s every 60s | 38ml + 962ml water | Massive Dev Chart | Pronounced grain with excellent sharpness. |
| Kodak Tri-X 400 | 400 | 1:100 | 20.0°C | 60:00 | Gentle inversions at 30 and 60 min only | 10ml + 990ml water | Community data | Stand development. Extreme edge effects, compensating. |
| Kodak Tri-X 400 | 400 | 1:50 | 20.0°C | 15:00 | Continuous first 60s, then 10s every 60s | 20ml + 980ml water | Massive Dev Chart | More compensating. Good balance of sharpness and grain. |