How to set up a film development timer on iPhone
In Agitate, open Develop and choose a published development time or write your own recipe. Verify the film, chemistry, dilution, temperature and each bath against the manufacturer’s instructions before starting. The app helps you follow the timing; the recipe and your measurements determine the process.
We make Agitate. This guide explains its workflow and limitations; paid features are noted below.
Get Agitate on the App StoreBefore you begin
Have the exact instructions for your film and chemistry, a thermometer and your prepared equipment. Set up and check the timer before handling chemistry. This guide explains the app workflow; it is not a substitute for the chemical manufacturer’s processing or handling instructions.
Step by step
Choose a source for the recipe
In Develop, select Find a published time or Write your own recipe. Match the exact film and developer combination. A familiar product name alone is not enough if dilution, exposure or processing conditions differ.
Check the complete sequence
Review the baths in The run before pressing Start. Confirm each planned duration and the agitation pattern against the source instructions. Do not fill a missing time with a guess merely because the timer allows a custom recipe.
Measure the actual temperature
Use your thermometer rather than assuming the liquid is at room temperature. For supported black-and-white processing, Agitate offers temperature conversion between 14 and 27 °C. It does not apply that conversion to C-41 or E-6.
Prepare the display and cues
Choose the display mode and check the cues before the run. A red screen can reduce distracting white light, but it does not make a phone safe around every light-sensitive material. Keep the phone away when the film or process requires complete darkness.
Start and follow the active step
Press Start when your process is ready for timing. Follow the current bath and agitation cues together with your chosen recipe. Keep handling and timing consistent so that a later comparison with another roll is meaningful.
Record what actually happened
Where appropriate, the running timer can be adjusted in 15-second increments. Only make a change for a reason you can record. Pro includes a development journal; note the actual temperature, timing and deviations so that a result can be repeated or investigated.
Temperature compensation has limits
A time adjustment is not a universal fix for the wrong chemical temperature. Use the supported range and the process-specific guidance. In particular, do not use a black-and-white conversion rule for a color process simply because both have a developer bath.
Agitate’s running temperature adjustment recalculates the remaining portion of a supported step. It cannot undo development that has already happened. Reproducibility still depends on your measurements and handling.
Why notes are more useful than a perfect-looking countdown
Two runs with the same displayed time may differ because of temperature, agitation, dilution or chemical condition. A short record of the actual setup makes the timer output useful when evaluating the finished film.
Start with a verified recipe and change one relevant variable at a time when your process permits it. Keep the recipe source with your notes. A timer organizes a workflow; it does not certify that the negatives will have a particular contrast or density.
Questions that come up
Does the red display make all film safe to handle?
No. Light sensitivity depends on the material and process. A red phone screen is not a certified safelight and cannot replace complete darkness when that is required.
Can Agitate adjust C-41 times for temperature?
No. Its temperature conversion is for supported black-and-white processing within 14 to 27 °C, not C-41 or E-6.
Can I change a step after starting?
The timer offers 15-second adjustments and supported temperature updates. Record deliberate changes so you know what process you actually followed.
Check the app details
See Agitate features and compatibility, or visit the official Agitate website. The App Store listing has current availability, pricing and in-app purchases. Screens and options can vary with the app version.
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