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Development time

Ilford Delta 400 in Perceptol

10:00 at 20°C (68°F), stock dilution, EI 200 (−1 stop).

Start timer · 10:00
Time
10:00
Standard
Dilution
Stock
Temperature
20°C
68°F
Box speed
ISO 400
B&W

All 5 times

DilutionEITimeTempAgitationEvidenceTimer
Stock200−1 stop10:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
Stock250−⅔ stop12:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+1200−1 stop12:3020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+1320−⅓ stop15:3020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+3200−1 stop18:3020°C / 68°FStandardManufacturerChecked Oct 2026Start 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°F19°C66°F20°C68°F21°C70°F22°C72°F23°C73°F24°C75°F
12:3011:1210:009:008:007:126:30

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

Dilution300 ml (10.1 fl oz) (one 35mm roll)500 ml (16.9 fl oz) (one 120 roll)
StockUse as mixed, undilutedUse as mixed, undiluted
1+1150 ml developer + 150 ml water250 ml developer + 250 ml water
1+375 ml developer + 225 ml water125 ml developer + 375 ml water

How they work together

Perceptol
Moderate acutance, normal contrast. Extremely fine grain, for when a loss of film speed is acceptable.
Ilford Delta 400
Modern core-shell T-grain ISO 400 film with fine grain and high sharpness; Ilford recommends exposure from EI 200 to 1600. Sold in 35mm and 120 (no sheet film listed).

Delta 400 in other developers

Other films in Perceptol