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Development time

Ilford Delta 400 in T-Max Developer

6:30 at 20°C (68°F), 1+4 dilution, box speed.

Start timer · 6:30
Time
6:30
Standard
Dilution
1+4
Temperature
20°C
68°F
Box speed
ISO 400
B&W

All 6 times

DilutionEITimeTempAgitationEvidenceTimer
1+4200−1 stop5:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+44006:3020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+4500+⅓ stop7:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+4800+1 stop8:3020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+41600+2 stops10:3020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+43200+3 stops13:3020°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
8:087:176:305:515:124:414:14

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)
1+460 ml developer + 240 ml water100 ml developer + 400 ml water

How they work together

T-Max Developer
High acutance, full film speed, normal contrast. Enhanced shadow detail in normally processed and push-processed film.
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 T-Max Developer