What kind of container should I use for a water bath for film development?

What kind of container should I use for a water bath for film development? It has to be big enough to contain the bottles for the six step E6 process. I was thinking a plastic bin, but I'm not sure.

Hello everyone. I do not know the quantity of liquid each bottle will contain but you could try a variation on the Igloo I use to keep my developing chem's & wash water for black & white film. Igloo, and other brands, come in various sizes. For the occasion 4x5 is used here, a much larger Igloo, normally used for beer & other assorted food & drink at races, is put into action. Temp's are "adjusted" by addition of hot or cold water & stay stable well over an hour when the lid is open. Please note there are 6 "big" bottles, each a "recycled" drinks #1 PETE bottle. Bill

Would a Plastic bin work with an element installed in it, or would the heat be too much for the plastic?

would the heat be too much for the plastic?

The heat is unlikely to have an impact on the plastic, with a few caveats: Jobo use ceramics spacers of roughly 1/4" no more than 3/8" to keep their heating element away from the processor's plastic tub. If you use a heat element meant for (dish?)washing machines and mount it through your bin's wall you should be fine too. Looking at water heaters for tea I notice: Full metal constructions seem to get along without either overheating protection or demanded minimum amount of water. plastic constructions usually demand minimum filling to prevent heating elements from damaging them.

In general I'd worry more about electrical safety than anything else.

Gotta say, through a lot of years of "al fresco" developing sans darkroom, temp was not a big deal. Good thermometer and time adjustment (as needed) with a basic water bath does the trick. The cooler is a brilliant idea. Soon to get back, by necessity, into developing film. Can't imagine it has gotten more difficult, though a lot of things have. :D

I always used print developing trays, because that is what I had around.

 

My system for E6 (40 years ago) was to put 8 oz. in plastic containers

(like for food storage) and set them in the print tray at (hopefully) the

right temperature. For developers, I would test with a thermometer

just before pouring in, and also keep the tank in the water bath with

a nearby thermometer.

 

Then I had a bowl with warmer water to add to the tray, if it was

cooling too fast. Estimate the relative volume needed from the

temperature differences.

 

Do the two rolls, capacity for the 8 oz., and discard.

I've always used a grey dish pan, the kind restaurants collect dirty dishes in, maybe 6-8" high. It doubles as my print wash tray with an old Kodak tray siphon.

A Jobo CPE2 is the ideal solution. Prior to owning one I made a tempering bath out of a flower planter trough - about 2' by 8" by 8" deep. A 500w laboratory heater-stirrer at one end kept the water temperature right. However, I see that those things are uncommon and expensive these days.

 

Check out aquarium suppliers for submersible pumps, heaters and thermostats. As long as you prevent the heater from touching the plastic tank everything will be fine.

 

A heater and thermostat alone won't be sufficient to ensure an even temperature. A submersible pump circulating water from one end of the bath to the other is almost essential. In fact I fitted one to the CPE-2 to improve its performance.

Checkout Wal-Mart. They have a huge selection of plastic bins of every conceivable size & shape. Aquarium heaters with a stand off work well for maintaining. The real secret is volume. The bigger the bath the more it will maintain a temp. First & CD are the two critical baths so if you're good through the DC you're good through the rest of the process as its got a wider tolerance.

As above, I kept 240ml in little plastic containers, for easy pour in/out. I had lids for them, but if you put them in too deep water, they float and then turn over. I didn't trust the lids in that case.

 

I would fill a tray deep enough for them to not tip enough to spill if the lids leaked.

 

Then another tray for the 240ml Nikor tank. I didn't want the level high enough that it might pour into the tank.

 

I suspect I wasn't quite as good as I should have been, but they always came out close enough for me.

 

If you keep the average temperature over the time within spec, even if it deviates above and below, it should be fine.

I think the problem with most aquarium heaters is that they have a temp limiter on them so you don't fry your fish. The igloo is the simplest (and great) idea, but if you prefer something more complex you can do what I did:

 

 

 

It's a thrift store roaster-oven hooked up to a Raspberry-Pi that cycles the heating element on and off to maintain the proper temp. It's smart enough (mostly) to compensate for continued heating after the element is turned off and vice-versa. There's also a cheap aquarium pump that circulates the water.

 

Also great for cooking steaks (DYI sous vide).

A Rasperry pi is slight overkill for turning a slow cooker on and off. It needs a thyristor or triac interface, so you might as well just use a cheap light dimmer. But I guess it's not a real project these days unless you stick a microcontroller in it somewhere.;)

 

Aquarium thermostats of old-fashioned bi-metal design can be adjusted over a wide temperature range. I used one in my first darkroom in my early teens to keep the developing dishes at 20 celsius in a water bath made out of plywood(!) plus many coats of polyurethane paint. I think some tropical fish like it quite a bit warmer than that, and winding the 'stat up to 41 C shouldn't be too difficult.

Oh, the pi does more than just turn it on and off, - the tricky part is knowing when to turn it on and off. If your target temp is 102, the current temp is 102.1667 and the temp 1 minute ago was 102.2275, do you leave it off or turn it on knowing that it's going to take some time for the heating element to warm up and have any effect. Then, how long do you leave it on? If the temp falls below 102, and you're warming the water back up, you must shut the element off before it gets to 102 or you'll overshoot.

 

The Pi implements a partial PID controller. It's not perfect. It tends to overshoot the target temp when warming up. After awhile it settles down and stays pretty close.

 

I agree that a simple insulated container is perfectly adequate, - but it's not as much fun. :)

I use the bathtub for E6. All of my chemical bottles go in there, and I keep the developing tank partially submerged unless I'm actively pouring things in and out.