If you are a photographer working in alternative processes (e.g. cyanotype, platinum/palladium, kallitype) here is an app that allows you to easily process several prints concurrently.
Simply create a timer for your process, select the timer to run and add as many additional timers as you like. Each timer runs independently, so you can start and pause as required, for example start a second exposure as your first print enters the developer. When the timer has finished, a simple tap dismisses the timer.
You can add a "hard stop", for example after exposure, so you can retrieve your print from the contact frame and simply tap to resume the timer once you are ready to process. Theres also a "drip pause" process step that allows you to specify an interval between process steps to allow chemistry to run off before proceeding to the next step.
If like me you end up with lots of rolls of film before getting down to developing, you can also use this app to process multiple development tanks concurrently.
The colored icons at the left of the screen indicate the number of timers: blue means added but not running, green means running, yellow means paused and red means completed. Tapping on an icon scrolls the view to the corresponding timer, useful for when you have several timers going with many steps.