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Development time

Ilford HP5 Plus in Perceptol

13:00 at 20°C (68°F), stock dilution, EI 250 (−⅔ stop).

Start timer · 13:00
Time
13:00
Standard
Dilution
Stock
Temperature
20°C
68°F
Box speed
ISO 400
B&W

All 6 times

DilutionEITimeTempAgitationEvidenceTimer
Stock250−⅔ stop13:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+1320−⅓ stop18:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
1+3320−⅓ stop25:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
Stock50−3 stops9:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
Stock100−2 stops9:0020°C / 68°FStandardManufacturerChecked Oct 2026Start timer
Stock200−1 stop11:0020°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
16:1514:3413:0011:4210:249:228:27

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 HP5 Plus
Robust all-purpose ISO 400 film with a wide exposure latitude; Ilford's datasheet gives good results from EI 200 to 800 and push processing to EI 3200 with extended development.
Notes on this pairing
  • Accidental exposure only (film exposed below EI 250): usable negatives, lower quality.

HP5 Plus in other developers

Other films in Perceptol