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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, NegaKit’s corrections for a warmer bath or a reused developer.

  1. Film

    513 films have published times.

    Shanghai Photosensitive Materials Shenguang 400 · ISO 400 · C-41

  2. Developer

    Only developers with published times for this film.

    ADOX C-TEC C-41 Negative Kit 2 times CineStill Cs41 Color Simplified Kit 7 times Flic Film C-41 Home Processing Eco Kit 2 times JOBO C-41 Colour Negative Developing Kit 1 time

  3. Dilution

    The only one published for this choice.

    working solution

  4. Speed

    The only one published for this choice.

    EI 400 box speed

  5. Temperature

    The developer temperature the time was published for.

    30 °C 38 °C

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

NegaKit’s chemistry rule: a reusable black-and-white developer at stock strength +10 % for each roll already through it, a colour kit +2 %. One-shot developers and working dilutions are used once, so they get no correction; nor does a monobath, which NegaKit has no rule for.