ChemClock Film Timer

ChemClock Film Timer is an offline-first utility for home film photographers and darkroom enthusiasts. No account, no network—everything is stored securely on your device.

Explore a built-in seed library of 30 film/developer pairs, filter by ISO or developer, and get accurate, temperature-compensated development times using the standard time-temperature adjustment formula. Build a custom development sequence with pre-soak, develop, stop, fix, and rinse steps, each with its own duration, agitation cadence, and alert sound.

During a run, the app keeps your screen awake, shows the current step and remaining seconds, and uses haptics and voice announcements so you can focus on your prints. The Lock Screen widget lets you monitor progress at a glance, and Siri Shortcuts let you start a run hands-free.

Calculate tank volume for 35mm, 120, or 4x5 sheet holders and figure out exact stock concentrate and water needed for any dilution. Create custom film/developer profiles, share them via QR code, and export a printable red-light PDF reference card with your times, dilutions, and agitation notes.

ChemClock Film Timer turns chemical math into a simple, guided process—so you can spend less time calculating and more time creating.