Immersion Heater

The temperature of my darkroom is up and down all the time. A big pain for me. I discovered that when the temperature of the print developer varies too much, prints of the same negative can vary also. This bugs me. At present, I use a water jacket, i.e., I put the developer in a tray and put that tray in a larger tray which has an aquarium heater. This works up to a point. Because the heater doesn't have real temperature control, I have to figure out, for each session, what the setting will be in otder to keep the developer at 20C. Even within the same session, in particularly cold weather, I am messing with the heater all the time.

I plan to put more insulation in this darkroom but that is down the road a year or so. In the meantime, does anyone know of an immersion heater with temperature control that might work in this situation?

There are aquarium heaters with integrated, adjustable thermostat, at least over here. I got such even seemingly unused from a fleamarket.
Though typically they are intended for somewhat larger volumes than our trays. There are also extern thermostats with a dimmer function, to be put into the mains connection of a plain heater.

to give you an idea
https://eheim.com/en_GB/aquatics/technology/aquarium-heaters/thermocontrol/thermocontrol-25?c=1706

most aquarium heaters do have thermostat control with a little knob or screwdriver slot to adjust. They're also usually unmarked other than hotter is turn one direction. You should be able to find it on yours. Then place in your water jacket tray full of water with a thermometer and let it stabilize. It could take several hours to really zero in on the temp you want. If you're doing B/W it's not like you need super precise, just ballpark repeatability.

good luck!!

Doran, a company started by a scion of the Arkay family. Doran made all manner of darkroom things. I've used one of their immersion heaters for RA-4 and Cibachrome with great success (was Cibachrome 75°F??) These are available used, not sure about 20°C. In the winter I use an electric oil filled radiator, it's on wheels, quite compact. Keeps the darkroom nicely at 68F.

I have a Zone VI compensating timer, I rarely use it, but these things work. I think temperature and time are incredibly important to producing, and reproducing good black and white prints.

I try to always check solution temps when printing, cold developer is difficult. Consistency is what I strive for.

I solved the heating problem by buying a used Jobo CPP2 processor with a lift arm, tanks and an expert drum. While they have become more expensive they do help produce consistently good development of film and prints. In the end I found the expense more than worth it.

I solved the heating problem by buying a used Jobo CPP2 processor with a lift arm, tanks and an expert drum. While they have become more expensive they do help produce consistently good development of film and prints. In the end I found the expense more than worth it.

Can you get a dish-warmer, that's the easiest.

When you do insulate the darkroom make sure it's the walls, ceiling and just as importantly the floor, it's not cheap but definitely worth it, and then I now leave a small heater on low.

IAn

The dishwarmer concept was taken over by Kaiser for lab trays. The heat transmission through a likely not perfectly contacting bottom of a tray may be less than by an immersed heater. Also there is only, at best, a indirect temperature control.

You might visit this site: https://anovaculinary.com/ There are a number of sous vide "cookers" on the market, we have one of these. While far more expensive than an aquarium heater, they allow setting a desired temperature easily and offer close temperture control. They circulate the water for even heating, and warm up quickly. We use ours in cooking to assure the perfect medium rare steak, I haven't tried in in the darkroom yet.
Here are specs for the Anova Nano, a compact model. https://anovaculinary.com/anova-precision-cooker/nano/ Looks like it should do the job for W, or color or steak!

Another issue wish dish heaters might be electrical safety in case of rinse from above.

Seed starter warmer stuff.
Amazon VIVOSUN Durable Waterproof Seedling Heat Mat Warm Hydroponic Heating Pad

Cinestill sells a purpose made immersion heater for $100. I have one and love it.

https://cinestillfilm.com/products/...emistry-and-precision-film-processing-at-home

I know of folks who use pet warming pads under the tray with developer, water proof, at high temp seems to keep chemistry up to 68 degrees F. When I had a purpose built darkroom with a true darkroom sink I had a constant control water supply that circulated around all my trays at 68 F. In those days water was cheap.

GRHazelton said:

You might visit this site: https://anovaculinary.com/ There are a number of sous vide "cookers" on the market, we have one of these. While far more expensive than an aquarium heater, they allow setting a desired temperature easily and offer close temperture control. They circulate the water for even heating, and warm up quickly. We use ours in cooking to assure the perfect medium rare steak, I haven't tried in in the darkroom yet.
Here are specs for the Anova Nano, a compact model. https://anovaculinary.com/anova-precision-cooker/nano/ Looks like it should do the job for W, or color or steak!

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I ran across a barely used sous vide cooker at a thrift store for $30 and it works wonders in a 8x10 Kodak natural rubber developing tank. Great for tempering chemistry or keeping a reserve of tempered water on hand for whatever use. The thick walls of natural rubber like like a thermal heat sink and helps maintain temperature very nicely after about 30 minutes.

Lots of good feedback here. Thanks guys.

The heated pad under the tray would probably work but I am a little nervous about safety issues. Some of the ones I have seen online note that they are not totally waterproof and that makes me a little nervous.

The sou vide technique would work great for holding chemistry at a specific temperature but they are very …. vertical! I would prefer something lying down in the tray

The Jobo is also a good idea for temperature control and I have both an older CPE-2 and a more recent CPP2. I love these machines but they would complicated the printing process. I want to continue printing with trays. Having to load and empty the Jobo just for a print would be a pain.

I am leaning toward the aquarium heater with thermostat control. There are a lot of aquarium heaters that hold the temperature but only after you figure it out first. By that I mean, you have to put a separate thermometer in the water and adjust the heater until the water stabilizes at the temp you want. I need something with a built-in thermometer that I can set to a specific temp and then leave it alone. The heater would bring the water up to 20C and keep it there without my intervention. The temp in my darkroom can drift quite a bit so I need a device that can respond to the changes.

I will probably get such an aquarium heater in the near future and experiment with it in a water jacket .i.e, a developer tray placed in a larger tray. I will let you guys know the results.

Doc W said:

There are a lot of aquarium heaters that hold the temperature but only after you figure it out first. By that I mean, you have to put a separate thermometer in the water and adjust the heater until the water stabilizes at the temp you want. I need something with a built-in thermometer that I can set to a specific temp and then leave it alone.

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The ones I hinted at got a scale to set the temperature at.

You then only would need a themomether if you want to check whether that scale is up to the temperature accuracy stated in the data sheet, or when you doubt that there is enough water convection within a complicated set up.

Auer said:

Cinestill sells a purpose made immersion heater for $100. I have one and love it.

https://cinestillfilm.com/products/...emistry-and-precision-film-processing-at-home

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I have been using the ANOVA for several years now.

How is the Cinestill working? My Anova has one disadvantage, it has too many lights so I had to make a hood to cover it. (I like to leave the water at temperature while I load film into the tank for the next cycle.) I assume the Cinestill can shut off the displays, I hope.

I don't see the problem. As long as your dev is about 20C, or 5 degrees below or above, you just adjust your print exposure to compensate.

cliveh said:

I don't see the problem. As long as your dev is about 20C, or 5 degrees below or above, you just adjust your print exposure to compensate.

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Clive, that is one way to do it, for sure. I was thinking that Adams' notion of "emergent" development (if I recall that term correctly) would work here. I use that method from time to time when I feel that the developer might be losing its potency. At this point, however, I just think that controlling the temperature of the developer igive me one less thing to worry about.

I have to disagree a little with your temperature spread. I would never develop a print at 15C.

Kilgallb said:

I have been using the ANOVA for several years now.

How is the Cinestill working? My Anova has one disadvantage, it has too many lights so I had to make a hood to cover it. (I like to leave the water at temperature while I load film into the tank for the next cycle.) I assume the Cinestill can shut off the displays, I hope.

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I dont think you can turn the display off.
Once you have water up to temp tho, shutting it off and turning back on should be fairly quick, it heats fast.
It can do 0c to 95c which I understand most kitchen appliances cant go all that low if needed.
I use mine often and have been very happy with its performance and price.

Go to a home brew shop, they will sell heater pads that you put your keg of beer on. They work a treat under your developing tray, you put the temp probe in the developer tray. All of your electrical outlets should have a GFI on them so safety is not an issue.

Doc W said:

Clive, that is one way to do it, for sure. I was thinking that Adams' notion of "emergent" development (if I recall that term correctly) would work here. I use that method from time to time when I feel that the developer might be losing its potency. At this point, however, I just think that controlling the temperature of the developer igive me one less thing to worry about.

I have to disagree a little with your temperature spread. I would never develop a print at 15C.

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What is wrong at 15C that can't be corrected by exposure? I believe all developer constituents are still active at this temperature.

GRHazelton said:

You might visit this site: https://anovaculinary.com/ There are a number of sous vide "cookers" on the market, we have one of these. While far more expensive than an aquarium heater, they allow setting a desired temperature easily and offer close temperture control. They circulate the water for even heating, and warm up quickly. We use ours in cooking to assure the perfect medium rare steak, I haven't tried in in the darkroom yet.
Here are specs for the Anova Nano, a compact model. https://anovaculinary.com/anova-precision-cooker/nano/ Looks like it should do the job for W, or color or steak!

Click to expand...

OP needs to keep in mind that the typical sous vide has a minimum water line...the anova in the link is 2.56", and its range of control is 32˚-197˚F...darkroom range is covered.

Most less expensive units only go down to about 77F

cliveh said:

What is wrong at 15C that can't be corrected by exposure? I believe all developer constituents are still active at this temperature.

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IIRC, hydroquinone is much less active at 15C than metol, so working at 15 C with Dektol, which includes both, will give you different (lower contrast) results than if you work at 20C.