Darkroom Chemistry
Dilutions, temperatures and fixer — the maths of developing at home.
Dilution
How much concentrate and water for the volume your tank needs (it is printed on the tank or its instructions).
ml1 +- Concentrate
- –
- Water
- –
Development time
Your time at 20 °C (data sheet or Massive Dev Chart) corrected for your solution's temperature.
min°CDeveloping time–Fixer
Drop the film leader into the fixer and time how long it takes to clear: fix for twice that.
ssFix for–
My baths
Count the rolls each reusable bath has done. Capacity comes from the data sheet (rolls per batch).
Good to know
- Many developers are one-shot: dilute, use once, discard. The tracker is for reusable baths like fixer and stop.
- Some developers have a minimum amount of concentrate per roll; check the data sheet if your dilution is very high.
- For times by film, developer and ISO, the reference is Massive Dev Chart.
- With the time worked out, run the whole process with agitation beeps in the Development Timer.
Everything runs in your browser; your baths are saved on this device only.