Development time
Rollei/Maco RPX 400 in Perceptol
20:00 at 20°C (68°F), 1+1 dilution, EI 320 (−⅓ stop).
Start timer · 20:00- Time
- 20:00
- Dilution
- 1+1
- Temperature
- 20°C
- Box speed
- ISO 400
Development time
| Dilution | EI | Time | Temp | Agitation | Evidence | Timer |
|---|---|---|---|---|---|---|
| 1+1 | 320−⅓ stop | 20:00 | 20°C / 68°F | Standard | ManufacturerChecked Oct 2026 | Start timer |
EI is the speed the film was rated at when shooting. Evidence says where each time comes from: the manufacturer’s own data, a named test, a compilation or several agreeing reports (community consensus), or one person’s report. Times marked “not yet verified” come from secondary sources and haven’t been checked against a manufacturer datasheet. Where sources give different times, every one is listed and marked “sources differ”.
Other temperatures
| 18°C64°F | 19°C66°F | 20°C68°F | 21°C70°F | 22°C72°F | 23°C73°F | 24°C75°F |
|---|---|---|---|---|---|---|
| 25:00 | 22:24 | 20:00 | 18:00 | 16:00 | 14:24 | 13:00 |
Calculated from the 20°C (68°F) time using Ilford’s temperature compensation factors, not taken from a datasheet. Most B&W developers behave well between 18–24°C (64–75°F).
Mixing
| Dilution | 300 ml (10.1 fl oz) (one 35mm roll) | 500 ml (16.9 fl oz) (one 120 roll) |
|---|---|---|
| 1+1 | 150 ml developer + 150 ml water | 250 ml developer + 250 ml water |
How they work together
- Perceptol
- Moderate acutance, normal contrast. Extremely fine grain, for when a loss of film speed is acceptable.
- Rollei/Maco RPX 400
- Rollei describes a high-speed panchromatic film with good edge sharpness, high resolving power and fine grain (RMS 14) on a triacetate base, for available-light, sports and reportage work.
- Notes on this pairing
- Rated EI 320 in Perceptol.
RPX 400 in other developers
D-76
8:00
Stock · EI 400 · 20°C · 5 variants
HC-110
6:00
1+31 · EI 400 · 20°C
ID-11
8:00
Stock · EI 400 · 20°C · 5 variants
Ilfosol 3
6:30
1+9 · EI 400 · 20°C · 4 variants
Ilfotec DD-X
10:00
1+4 · EI 400 · 20°C · 2 variants
Microphen
7:00
Stock · EI 400 · 20°C · 4 variants
Rodinal
12:00
1+25 · EI 400 · 20°C · 3 variants
Rollei Supergrain
6:00
1+9 · EI 400 · 20°C · 3 variants
Other films in Perceptol
Ilford HP5 Plus
13:00
Stock · EI 250 · 20°C · 6 variants
Ilford Delta 3200
18:00
Stock · EI 3200 · 20°C · 4 variants
Ilford Delta 400
10:00
Stock · EI 200 · 20°C · 5 variants
Ilford FP4 Plus
12:00
Stock · EI 125 · 20°C · 7 variants
Foma Bohemia Fomapan 400 Action
9:00
Stock · EI 400 · 20°C · 2 variants
Harman Technology Kentmere Pan 400
23:00
1+1 · EI 320 · 20°C
Harman Technology Kentmere Pan 100
12:30
Stock · EI 100 · 20°C · 4 variants
Ilford Ilford Delta 100
15:00
Stock · EI 100 · 20°C · 7 variants