Lego Rotary Film Developer

[KingRollei]

I made one today out of Lego Technic pieces, to rotate a Paterson tank back and forth. Waiting for the electric motor and rudimentary programmable controller to arrive to finish. Then I'll experiment with timings as I haven't yet worked out a satisfactory way to keep the chems at a continuous temperature...

 

[dirk]

Once you are finishd, you need to post images of it. Creativity is alway good!

 

[Linsenbruch1]

Great. I did something similar in the early 70's. (Yes I am not a young member.) I made a machine for rotating my Tetenal Colour Tank. It was not made from Lego but from the early Austrian kind of Lego, called Matador and it was made from wood. It really was working very proper! But my son did not like it.

 

[cesare]

I made one today out of Lego Technic pieces, to rotate a Paterson tank back and forth. Waiting for the electric motor and rudimentary programmable controller to arrive to finish. Then I'll experiment with timings as I haven't yet worked out a satisfactory way to keep the chems at a continuous temperature...

For B&W temp won't matter, it'll stay close enough to 20C during the processing, so don't worry about that.

For C41/E6, the recommended temp variation is within 0.1C through processing, which is pretty difficult to achieve without a water bath. I'm fortunate enough to run a Jobo Autolab, but funnily enough i've ended up mainly shooting B&W where I rarely need the Jobo - oh well, i'm sure i'll do more colour at some point.

 

[Mal Paso]

I built a 1 gallon water jacketed E6 line from welded ABS sheet and old Kreonite parts back in the day. It would handle 20 sheets of 4x5 or 4 rolls of 120. The last of that went up in smoke in 2016. Fortunately I found some 4x5 Evolution hangers which are as good as my custom built hangers and I have a 1 gallon non jacketed B&W open top tank line. I haven't replaced the 35mm and 2 1/4 cameras but I'm up to 3 4x5s now. I got into digital while living in a small rental waiting to rebuild and that's my color fix for now.
The water jacket was about 40 gallons and easily held 1/4 degree F. Still have the Kodak Process Thermometer.

 

[Jan Tieghem]

Happy coincidence, I’m looking to build one myself. I’d do the electronic part with an Arduino based microcontroller, but still don’t know how to make the mechanical part. I’m very interested in how your project looks like!

 

[IvoB]

3D printing is the way to go

 

[KingRollei]

For B&W temp won't matter, it'll stay close enough to 20C during the processing, so don't worry about that.

For C41/E6, the recommended temp variation is within 0.1C through processing, which is pretty difficult to achieve without a water bath. I'm fortunate enough to run a Jobo Autolab, but funnily enough i've ended up mainly shooting B&W where I rarely need the Jobo - oh well, i'm sure i'll do more colour at some point.

I thought so, I assume that any slight drop in temperature will be compensated by the continual back and forth rotation. I'll start with Jobo timings and quantities

 

[KingRollei]

Happy coincidence, I’m looking to build one myself. I’d do the electronic part with an Arduino based microcontroller, but still don’t know how to make the mechanical part. I’m very interested in how your project looks like!

I went with lego as I had a ready supply of gears/cogs for the mechanics and a basic programmer. I hadn't thought of Arduino, now I do and I might follow you next!

 

[Jan Tieghem]

I went with lego as I had a ready supply of gears/cogs for the mechanics and a basic programmer. I hadn't thought of Arduino, now I do and I might follow you next!

Unfortunately, I've never used motors or gears for any project, so this will be the hardest part for me. Simple projects with microcontrollers are no problem for me, my darkroom has several timers and thermometers I made with AVR microcontrollers. I'll be back sooner or later with my results ...or struggles

 

[cesare]

I thought so, I assume that any slight drop in temperature will be compensated by the continual back and forth rotation. I'll start with Jobo timings and quantities

For B&W the agitation can change the developer behaviour, so you have to be a bit aware that this will change how things come out. I tend to use Xtol 1+1, and this seems to give me nice consistent results across film stock. Yes, you will probably get a reduction in development time compared to stand or tank flipping, and it's certainly a lot less effort! Temp dropping over the B&W development time will just mean slightly thin negs, nothing terribly bad happens. For colour, you get colour shifts - the different layers develop at the wrong rates relative to each other, so this is to be avoided.

The jobo rotary developers with rollers under the tank and a water bath are great for colour, but as I said, overkill for B&W where the change is less likely to matter (certainly if you are an amateur like me)! So, consider rotary for B&W as a time saver, and more consistent development rather than anything else.

 

[KingRollei]

Thanks, consistency is exactly what I hope for. My replenished Xtol regime failed on me a few weeks ago and I have no definitive reason why, just lots of possible theories. I'll always test first in future or just go back to mixing fresh dev

 

[Jan Tieghem]

Then I'll experiment with timings as I haven't yet worked out a satisfactory way to keep the chems at a continuous temperature...

I have used a Jobo now and then. I followed the advice to cut dev time with 10% to compensate for the continuous agitation and that works great for me.

 

[cesare]

Thanks, consistency is exactly what I hope for. My replenished Xtol regime failed on me a few weeks ago and I have no definitive reason why, just lots of possible theories. I'll always test first in future or just go back to mixing fresh dev

With rotary, the total liquid is quite a bit lower, and you hit the minimum Xtol per film. I think it's around 250ml to cover two 120 films in a jobo tank when doing rotary development. Since the limit is 100ml of Xtol per film, my regime is to measure in 200ml (the minimum for the two films) and to top up with another 200ml of water to bring it to 400ml total. I choose the top up water temp to bring it to 20C, then just pop it in the rotary tank and all is good.

So for me, I don't bother with any replenishment, just use neat Xtol watered down to 1+1 for dev purposes. It's simple and consistent, no risk of contamination, and all I need to do is track the date I mix up the batch.

 

[Mal Paso]

I also switched to one shot developing after some mottling of sky tones. I spent about $150 on raw chemicals and a used triple beam scale and mix most of my own chemistry now. A gallon of Hypo Clear is the simplest thing and costs about 50 cents. I'm currently using X-15 Developer 1 to 1 but I can easily switch to something else.

I found a set of Evolution Film Hangers and bought 4 Yankee 1/2 gallon tanks so the only motorized thing is the GraLab Timer.