DIY Automated Film Developer

[JChrome]

So I've found a number of folks who've tried their hand at this but I never see much of a follow up. I think this maybe because they've found it too tough or just bought a Jobo instead.

I think that my proposed system would be better than a Jobo and cheaper.

Disclaimer, I've very little time for these projects but I think this could be finished over a couple of days.

I don't have a diagram yet but will upload one as needed.

Proposed functionality: Storage tanks for the chems. The user would need to input the chems (the correct amounts, dilutions and at the right temperature). The user would also have to load the tank with the film on the reels (paterson design). Then, once these two items are in place, navigate to a locally-hosted webpage which allows the user to change the times associated with each wash, dev and fix. Hit the button and it takes 20-30 minutes and finishes.

First:
Water, Developer, and Fix containers.

These would be gallon jugs, positioned upside down, with the bottoms cut off. These could easily be placed in a water bath, if needed, but right now I don't think it is.

Second:
Connection between the jugs and the main film tank. First, this is a gravity fed system. At the bottom of each chem-container jug there would be a sprinkler solenoid-controlled valve (can be had for $15 per piece). After the sprinkler valve, all lines feed into one main PVC pipe which then connects to a garden hose connection.

Next comes the Film Tank. This is arguably the most complicated piece (the agitation specifically).

Third:
Film Tank.
3A) The lid. It would be screw on (needs to be removable so that you can input the reels). It would also need to interface with the garden hose connection.
3B) Tank itself. Not too complicated. Just needs to be the same width as a Paterson 3 reel tank. This will have a "main shaft tube" going up through the center to hold the reels.
3C) The bottom housing which contains the agitator. This is perhaps the most complicated part. I am thinking of going the route of a chemistry stirrer (you know, like those white pills you put in flasks). There would be a housing within the tank that would contain a computer fan motor with some neodymium magnets attached. This fan is variable (hooks up via USB) so I can control the speed and the length of time of agitation. The part thats difficult to explain is that the stirrer would be in the center of the tank and positioned with the "main shaft tube" above. So it would bring chems from the bottom and shoot them up the the tube to flow back down.
3D) The bottom cap of the Film Tank. This would be tapered so the chems flow downward and reach the last sprinkler valve. The sprinkler valve would open and let all the chems flush down into a receptacle.

Fourth:
Controller for the sprinkler valves. There is a "OpenSprinkler" circuit board which alls you to program when the sprinkler valves open and close. This attaches to a raspberry pi. I could write some software to time everything perfectly.

Materials:
(4) Sprinkler valves. Approx $70
(1) Raspberry Pi - Already have
(1) OpenSprinklr Pi - Approx $90
Various PVC pieces (will outline later) - Approx $60
Garden Hose connections. Approx $20
Teflon tape - Already have
Silicon Glue - Already gave
PVC Cement - $5

I would estimate this to be less than $300

What do you guys think? I think it sounds awesome and came up with it in a dream last night. Well, anything is better than spending $4 per sheet of 4x5 developed at the local lab! I would make my money back relatively quickly (I shoot something like 20 shots of 4x5 per week). And this could easily be altered for E6 or C41 (which I don't shoot so much of due to the cost).

 

[Phil_F_NM]

While it's a cool idea in theory, I've worked in labs for years, much of which was maintaining both dip and dunk as well as roller transport machines.
The weak links are your hose connections and your valves.
Even in working labs with both those components designed to transport caustic and acidic materials, they develop scale buildup and corrode. Using a simple garden hose, with a textured material on the inside would lead to grains of chemistry getting into your tank. So then you need filtration which is going to have to be pressurized and not simply a gravity fed system. Filtration needs to be on the same scale as the grain in the film so .5 micron or smaller should be used. Staged filters are good with an open cell type then a fiber filter but they need to be cleaned with every two or three runs.
Keeping chemistry the same temperature is critical as well. A degree or two down at the temps used for black and white can alter everything, while a variation of 5 degrees up at C41/E6 temps is allowable.
After all is said and done, you get to the volume developing part. Do you shoot enough film to spend the time and money to build/operate/maintain/feed the new processor? Chemistry doesn't stay around forever and should be regularly replaced, not just replenished.
Good luck if you try it and post your results.

Phil Forrest

 

[JChrome]

The weak links are your hose connections and your valves.
Even in working labs with both those components designed to transport caustic and acidic materials, they develop scale buildup and corrode. Using a simple garden hose, with a textured material on the inside would lead to grains of chemistry getting into your tank.

I would agree that these are potentially the weakest links. Don't you think that a simple rinse of water after every dev cycle would help a lot? There would be a lot of water going through that hose.

Can you elaborate on the "textured material on the inside would lead to grains of chemistry getting into your tank". Do you mean that the chemistry would stick to the inside of the hose? Couldn't I use another style of hose?

Keeping chemistry the same temperature is critical as well. A degree or two down at the temps used for black and white can alter everything, while a variation of 5 degrees up at C41/E6 temps is allowable.
After all is said and done, you get to the volume developing part. Do you shoot enough film to spend the time and money to build/operate/maintain/feed the new processor? Chemistry doesn't stay around forever and should be regularly replaced, not just replenished.

I don't foresee the temperature being an issue. My apartment is kept at a constant 72 degrees which the chems would adopt in kind. I'm not worried about being that precise. I never have been.

I do shoot a lot of 4x5. Its worth it to me to develop at home using the Paterson tank even without this setup.

Good luck if you try it and post your results.

Many thanks for the corroboration and feedback!

 

[harpofreely]

K.I.S.S. - this is as promising as anything I've seen: http://petapixel.com/2014/01/20/using-legos-develop-film-automatically/

 

[Phil_F_NM]

You can only flush with distilled water and you must use an antifungal agent. These machines build up algae quite quickly which will grow on any surface that has texture. The garden hose, a seam in the plastic of your valves, the lip between hose and valve, corners of your tank, anywhere it can. It will be red algae as it won't have any light for photosynthesis.

You could and should use another style of hose. You'll have to look for hoses and valves that can withstand exposure to strong bases. If you're using a stop bath, you'll have to do the same for acids. In the AGFA minilabs for C41 and E6 there are valves composed of three different kinds of plastic for the pH of the chemistry. Even so, the valves and seals break down.

For agitation, you can go the dip-and-dunk route and use a bubbler system where you have a diffuser on the bottom of your tank with nitrogen gas bubbling up. A solenoid operated valve can open and close the line at your specified intervals. Low pressure Nitrogen is just about the safest thing to work with as well. The initial investment of a tank and the regulator is your biggest expense.

You're going to have to think about precipitate as well and you'll have to have a filtration system. Find a low-temp or zero-temp fluid pump to get your chemistry through a fiber filter at the very least. The filters in minilabs look like solid blocks of urethane but they actually pass liquids though they must be under pressure. All this because your chemistry with precipitate and form granules which you will see on your film.

I'm all for the DIY solutions but at the same time I know the ins and outs of photo processing and all the intense headaches. These headaches are why minilabs are being scrapped or sold for pennies on the dollar. Businesses can't afford to feed them the chemistry they need to keep the machines running economically. The latest lab I worked for bought a dual-format wet/dry minilab, complete with laser scanner, CPU, network, screen, tanks and extra fresh chemistry (in jugs) for a few hundred dollars back in 2011. That machine originally cost over $50,000.
You might think about just buying a used minilab...

Phil Forrest