I spent some happy minutes this evening “re-engineering” my film-processing robot, and thought I’d share…
The need for this device came about when the motor on my old “uniroller” base burnt out – a terrible shame, because after some years of film developing, I’d grown to love it. Unlike the inversion method that you learn for processing film in single tanks at school – having the film reels sloshing backwards and forwards horizontally on a motorised base pretty much guarantees nice even development, not to mention consistent results! Development is about 10% faster too, due to the constant agitation!
Anyways, my Uniroller motor died, so I cannibalised some of the parts and built this:
The little fan is just for aesthetics – but it runs nicely and the slight wonkiness of the large drive wheels sloshes the chemicals in the tank around in a way that means a reversal cycle isn’t necessary. The plastic thingo on the bracket at right stops the tank from wandering off the wheels, and the plastic lunchbox is a homemade 240VAC/12VDC power supply to drive the 36rpm motor connected to a length of 1/4″ all-thread.
The whole thing is mounted on a former easel base (for some reason, I have a silly number of easels of similar size) – which gives it a cleanable, flat base with grippy rubber feet.
This latest incarnation is much quieter too – probably because I’ve have tightened the nuts and bolts better = less vibration overall. The pictures above show the device with 120 reels, and a 4×5″ reel, but of course I process 135 film in it too – I can fit about 5 reels in a tank in one go, and it uses only 500ml of chemistry (so, using Agfa Rodinal at 1:25 – that’s a miserly 19ml of developer), or 600ml for the larger 4×5″ tank.
Coupled with the handy “Massive Development Chart” app on the ipod – a customisable reference to most film/developer combinations, AND a useful process timer with temperature compensation… I’m all set to process film, and have been using this system for about two years now.
The other innovation is this update is the “on/off” switch – an OH&S improvement, because previously I switched the whole thing on and off from the power point, and when your hands are wet and so on… The switch is on the DC side of things, for the same reason!!