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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.

Develop for 11:00

  1. Film

    513 films have published times.

    Rollei RPX 25 · ISO 25 · B&W

  2. Developer

    Only developers with published times for this film.

    ADOX Rodinal 2 times Compard R09 One Shot 2 times Compard R09 Spezial 2 times Compard R09 Studio 2 times Ilford ID-11 1 time Ilford Perceptol 1 time Kodak D-76 1 time Kodak HC-110 1 time Kodak XTOL 1 time Rollei RLS 1 time Rollei Supergrain 3 times SPUR Acurol-N 1 time SPUR HRX 1 time Tetenal Ultrafin Plus 1 time

  3. Dilution

    The only one published for this choice.

    1+70

  4. Speed

    The only one published for this choice.

    EI 20 pull 0.25 stops

  5. Temperature

    The only one published for this choice.

    20 °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.