While many people are familiar with Massive Dev Chart’s free online development time charts; they also have an iPhone app. Which I think can be a great tool to add in the dark room. I’ve spent time on ebay looking for a proper clock. I’ve even recorded myself into an audio file, where I count off significant time markers in my development workflow. The Massive Dev Chart app solved most of my problems. The timers are customizable and very well done. For you tray developers, where everything is done in the dark; the app provides something extra. It allows you to keep the screen on, while developing by limiting the amount of light the iPhone produces.
While I’ve used this feature, I have made some slight modification to my iPhone where I was confident in not manipulating my development. This includes taping regular paper and covering the top portion of the screen. Therefore the only thing I can see is the timer and the stop/continue/reset buttons.
Secondly, another advise is to make sure to place the iPhone into airplane mode and stop local notifications. This can accidentally place brighter graphics into the screen.