I need to find a method for bringing a water bath to 105 F, and keep it there. Never had a color darkroom, but I know that chemical temps were critical in color procedure. Perhaps I should be looking for something used with that process. What should I be looking to buy for this purpose? I appreciate any responses, and thank you in advance.
You will need a big ass water heater for this.
How much water? What is the room temp year round?
I have looked for these as well but have found that there is a lot of heat required to bring up and keep a bath at such at temperature.
Calumet, IIRC, had a device that would recirculate the water in your sink in order to keep it constant. In a web search it looked as though they were about $600 and finding any specs on them was next to impossible.
If the bath is just a print tray, you might try Nova. They used to make a tray warmer. I have one and it runs 220V and does a great job for keeping Lith developer toasty when I need it as well as keeping paper warm when I want to coat it with gelatin.
For what do you want to use this?
Jobos have a heater for maintaining temperature of a water bath. I found a Doran brand dohicky at the local used camera shop which is what I use (just started doing C-41 and E-6). Same idea as jobo but much cheaper. It came with a heater appliance that you lay in the bottom of the tub (use hot water from the faucet close to final temp so you don't have to wait so long for it to heat up). Seems to work well enough.
Someone else also posted here about using a slow cooker. Don't know if it keeps the temp in a narrow enough range but you can find them cheap, might be worth a try.
I've also heard of people just getting hot water from the tap, starting a little above 105* and letting it cool naturally. Start developing at around 107* and it averages out to about the right temp. First dev is the most critical, after that the temp becomes a little less critical and should drop slow enough to not be a problem as long as the bath is large enough to maintain some heat.
You can also modify most regular aquarium heaters by removing the stop bit on the rheostat and playing with it until you get it in the right place. 105 might be pushing it a bit though- I have achieved 100 degrees with one before. Why 105? Shouldn't it be 38C or 100.4F for color processes?
Robert, you might check out the used Precision Scientific waterbaths here http://www.lehmanscientific.com/baths2.html
They have a couple under $200 -- more precision than you need, but a possibility.
Crock pots are used by some -- just a matter of testing their lowest setting to see if it is right for you. Thrift stores?
Jobo processing units -- find one that is broken except for the water heating unit?
I think I'll start ask this question over on the B&B Carbon site -- to see what others are using.
Vaughn
PS -- Robert is asking because I might have got him hooked on carbon printing this weekend -- and one needs to hold the pigmented gelatin at 105 to 110F for a few hours.
Heating the water bath is easy. What about us in warm climates where the water comes out of the tap at 27C? I've yet to see any kind of practical water chiller. I've entertained the notion of making a loop of tubing through my chest freezer and circulating water through it, but it would freeze unless I used antifreeze and a water-to-water heat exchanger. So I just use ice, and a lot of patience.
Science is what we understand well enough to explain to a computer. Art is everything else we do.
--A=B by Petkovšek et. al.
A decent recirculating thermoregulator will easily keep temps within plus/minus a tenth
of a degree F, but will require about a thousand watts and cost about a grand. Much more accurate than a water-tempering darkroom valve. These are almost impossible to find used, and one probably wouldn't want to rely on a used one anyway. Jobo tempering boxes take longer to reach equilibrium and are not as accurate, but will do
the job in most cases for modest chemcial volumes (a liter or less). General immersion
heaters are pretty tricky and will prove to be a headache for temp fussy processes
like RA4.
Cooling is easy with a good thermoregulator. Just throw in a plastic cube or two of picnic box. Or lacking that, just have a slow trickle from a cold water line. But if this
is just for carbon printing, I'll admit that a thermoregulator is overkill. For my analogous
dye transfer work, to keep the dyes and transfer surface warm, I just use a couple of
old Salton hot trays that I picked up on fleabay for next to nothing. Even an immersion
heater and little fountain pump would probably work.
Meant to say cube or two of blue ice, picnic box type.
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