Tools
Development calculator
Choose a film and a developer, then the dilution, speed and temperature the time was published for. You get the maker’s time with the datasheet it came from — and, if you need them, corrections for a warmer bath (NegaKit’s rule) or a reused developer (the maker’s own rule, where it publishes one).
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Film
Ilford Delta 400 Professional · ISO 400 · B&W
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Developer
Only developers with published times for this film.
Acufine 11 times ADOX FX-39 Type II 1 time ADOX Rodinal 9 times Fomadon Excel W27 2 times Fomadon P 2 times Fomadon R09 1 time Ilford ID-11 20 times Ilford Ilfosol 3 12 times Ilford Ilfotec DD 5 times Ilford Ilfotec DD-X 12 times Ilford Ilfotec HC 15 times Ilford Ilfotec LC29 22 times Ilford Ilfotec RT Rapid 10 times Ilford Microphen 26 times Ilford Perceptol 11 times Kodak D-76 20 times Kodak HC-110 15 times Kodak T-Max Developer 12 times Kodak T-Max RS 4 times Kodak XTOL 28 times Tetenal Ultrafin Plus 11 times Tetenal Ultrafin SF 18 times
How the numbers are worked out
Only what is published
Every time is a maker’s or a source’s own, read off the datasheet linked beside it. Speeds, dilutions and temperatures are the ones published: nothing is extrapolated, so a push nobody published is simply not on the list.
A warmer or cooler bath
For black-and-white film only, and only between 18 and 26 °C: about 9 % shorter for each degree warmer, rounded to 5 seconds. It is the rule NegaKit’s developing timer uses, which follows Ilford’s and Kodak’s temperature charts closely in that range. Colour processes and monobaths are not corrected.
A reused developer
Only where the maker publishes a rule for a reused developer, and then the maker’s own, with its words and a link to the sheet. A maker that is silent gets no correction: the page says so rather than borrow a percentage. Where the rule is printed for a fixed volume, we scale it to your tank in proportion, and past the maker’s stated capacity we tell you to mix fresh developer.