Aquarium Chiller to keep tempering bath at 20C?

[Kino]

Just gathering wool; speculating on how reasonable it would be to construct a tempering trough to keep chemistry @ 20C/68F.

My tap water is getting too warm again and I really hate very short developing times with adjusted temperature estimates.

Was thinking of a relatively inexpensive aquarium chiller with an internal pump to circulate into a 2-3 gallon trough that would keep my chemistry cooled to the right temp. Could even reserve a spot for the developing tank in-between agitation cycles.

Also thought i might be able to recirculate the water bath water on my Nova Slot Processor and chill that as well, but that's less critical.

Thoughts?

I currently use just chilled water now in an inelegant ballet to obtain the ideal temperature and, like all lazy, entitled people, thought I could somehow over engineer a solution for a tiny problem...

 

[koraks]

I'd just use the time/temp conversion chart and adjust the development time to the temperature of the developer. Don't worry, be happy.

 

[pentaxuser]

I had never thought of a chiller as except in very recent years where official heatwaves have been more frequent my cold water tap if left to run for a moment or so never delivers water above about 20 C

I agree with korak's suggestion which will work in all except the more extremely hot area

Apparently there are places such as Arizona where the cold tap can deliver water above 90F I don't think the time temp charts such as Ilford's cover such extremes but do not know if this indicates that beyond its range you should attempt to cool the water by some means

pentaxuser

 

[Alan9940]

Live in Arizona...my "cold" tap water is currently running about 83F. Developing film at this temp might be possible, but I wouldn't recommend it for a number of reasons. I keep a gallon of tap water and about 1/2 gal of distilled water in the fridge for tempering a water bath and mixing chemicals. During the hotter months (about 6 months of the year), I develop film at 75F. Roll film is loaded into stainless steel tanks and kept in the water bath throughout the process. Since I develop only B&W film, maintaining a strict temp is not all that necessary, but I use a compensating timer that monitors the bath.

LF film is developed on my Jobo in Expert Drums with a block of ice in the upper water trough to keep the water bath temp where I need it. I'll admit that doing all this when I lived in central Vermont was a lot easier because everything had to be warmed up for most of the year. But, hey, we do what we need to...

 

[abruzzi]

I live in New Mexico and for about 2/3 of the year the tap water is above 20C. So I've adapted my process to not by adjusting dev times, but sticking the mixed chemicals in the freezer. I basically mix up the chemicals for the tank, stick them in the freezer to cool them down. On a hot summer day that can take 8-10 minutes. I mix up the chemicals first, then while the freezer is cooling them, I load the film into the dev tank, then for whatever time is left before hitting 20C I soak the film in tap water. I don't bother with the temps of the stop or fix. They're kept indoors so they should be in the vicinity of 25-28C or so.

Cooling the developer doesn't take that much extra time becuase I mix it and freeze it before anything else, so while the freezer is bringing down the temps, I prepare everything else.

 

[Andrew O'Neill]

I've only ever used ice, and this is from living through very humid, southern Japan Summers.

 

[Neal]

I actually tried using an inexpensive (~$100) aquarium chiller once. It worked as long as the room temperature wasn't very hot. My darkroom was in the garage so in the summer there was no benefit. My almost completely uninformed guess is that one of the cheap ones will work if the room temp is below 80°F. You might have to pay more but visiting a fish store might be worth it for the advice.

Good luck!

 

[boring old man]

I've been leaving water in the fridge, and mixing to tweak the temperature.

 

[Kino]

As I said, it was just a casual, wool-gathering idea...

After some research, I thing I'll just get a dormitory refrigerator that can do multiple duties and keep some water in there for the Summer.

 

[Bill Burk]

My 'chiller' is a coil garden hose that is in-line with my sink water supply.

When not in use, it fastens under the sink and just sits there.

But when I need it, I bring out an ice chest, fill it with ice and drop the coil in it.

I think a copper tube coil might have been a better choice, but this trick works for a few degrees.

 

[Paul Howell]

Like others I live in the desert Southwest, this has not been a very hot summer, in the past I've had tap water at 90 degrees. I use ice to cool my chemistry down to 68 to 70degees, then a DYI chiller for wash. I have 5 gallon bucket with a coil of copper tubing, the tubing is water tight so I can a mixture of water and ice in the bucket, Tap water goes into the coil at the top and comes out on the bottom. Although Perma Wash claims that it only takes 1 minute wash, 1 minute in perma wash and a final 1 minute wash for final wash I wash for 5 mintues. I had to figure the ratio of ice to water so keep the wash water up to 68 degrees, it easy to add too much cie and wind up with water temp around 50. I use tap water to wash prints, to date have not any issues with hot water temps for RC or FB prints but know of folks who have had emlusions coming off prints when using 90 degree wash water.

 

[gordrob]

I ran into a guy from Arizona a couple of years ago that was up here vacationing and he was amazed how cold our water is. He said he had been using a wine fridge that he had picked up second hand to keep his chemicals chilled because of the high temperature of his tap water.

 

[Paul Howell]

In the summer I keep our town house at about 75 degrees, my mixed chemistry just a tub of water until the temp is around 70. I don't think it makes a difference, but I want to avoid any sudden change in temp. In the old days, meaning 60s and early 70s, I think film emulsions were softer and there was a risk that the grain will of actuality move when subjected to a sudden change in temp causing loss of sharpness. At least that was the theory, I was taught to add hardener to rapid fix. I recall reading in a Kodak guide to film development to keep all temps from developer to wash within 3 degrees. In the Air Force we kept B&W withing 2 degrees and Color within 1 degree. With modern films I doubt this is an issue, so just out of habit.

 

[Alan9940]

I'm curious about the copper coils you folks are using as a "chiller." I understand that if the coil is sitting in a bucket of ice water the heat transference of the copper is going to be pretty fast, but... Tap water can't enter the top of the coil at, say, 83F and emerge out the bottom end at 68F, right? Water flowing through the coil can't possibly cool that fast? Is the effective cooling only a degree or two?

Having a setup that would allow me to obtain water at even close to "normal" processing temps for B&W would make my life a lot easier; especially for LF film. I can do the "dance" to get all the processing chemistry to the correct temp, but the wash water is a bit of a pain. I can't keep enough water in the fridge to handle 8x10, if my wife has done our batch cooking for the week. It's filled with food! Geez...

 

[koraks]

Tap water can't enter the top of the coil at, say, 83F and emerge out the bottom end at 68F, right? Water flowing through the coil can't possibly cool that fast? Is the effective cooling only a degree or two?

Depends on how fast you let it run, what the delta-T is, thermal mass of the copper, dimensions of the coil, etc.

 

[Bill Burk]

I'm curious about the copper coils you folks are using as a "chiller." I understand that if the coil is sitting in a bucket of ice water the heat transference of the copper is going to be pretty fast, but... Tap water can't enter the top of the coil at, say, 83F and emerge out the bottom end at 68F, right? Water flowing through the coil can't possibly cool that fast? Is the effective cooling only a degree or two?

Having a setup that would allow me to obtain water at even close to "normal" processing temps for B&W would make my life a lot easier; especially for LF film. I can do the "dance" to get all the processing chemistry to the correct temp, but the wash water is a bit of a pain. I can't keep enough water in the fridge to handle 8x10, if my wife has done our batch cooking for the week. It's filled with food! Geez...

As koraks said. Temperature is controlled by rate of flow.

Cold water doesn't get much above 72-degrees F here at the coast of northern California, and the bucket of ice brings it down those few degrees to 68-degrees F at a reasonably slow rate.

 

[Paul Howell]

I'm curious about the copper coils you folks are using as a "chiller." I understand that if the coil is sitting in a bucket of ice water the heat transference of the copper is going to be pretty fast, but... Tap water can't enter the top of the coil at, say, 83F and emerge out the bottom end at 68F, right? Water flowing through the coil can't possibly cool that fast? Is the effective cooling only a degree or two?

Having a setup that would allow me to obtain water at even close to "normal" processing temps for B&W would make my life a lot easier; especially for LF film. I can do the "dance" to get all the processing chemistry to the correct temp, but the wash water is a bit of a pain. I can't keep enough water in the fridge to handle 8x10, if my wife has done our batch cooking for the week. It's filled with food! Geez...

The tap water is between 80 and 90, might be higher at times. The tubing is wound tight. I attempted to take an image but no matter how low res I use I cannot post it. With 7lb of ice the water will drop to 55 to 60 degrees, with around 3.5 pounds the temp is around 70 degrees and will keep the temp for the 5 minutes I need to wash film. If the tap water is really warm I will add more ice. My only grip is that I have to monitor the process for the full time to keep the temp in the zone. I use a hurricane type roll film washer for up to 8 35mm rolls or a deep pan for sheet film. I think I started with a 10 foot length of tubing. My last full size darkroom was built out in my garage, it had AC, and I found a water chiller at an industrial salvage lot, had been in a meat processing plant.

 

[mshchem]

Remember that you don't have convection helping if you try to chill from the bottom. Would need circulation of some sort.
I'm fortunate, my darkroom stays nice, I use a little extra heat in the winter.

Tap water temperature is cool (in part) in areas where water mains are buried deep. Here everything is minimum 6-8 feet underground to prevent freezing. Thus water is cool year round. Places like Florida may just be right under the surface.

 

[titrisol]

It is very possible, as long as your room temp is not very high and you dont over exert the coil.
If your room temp is too high you might want to add a stainless coil before the chiller and dip that in chilled water
In the lab we used something like this to cool down experiments, I wonder if you can find one in a college surplus sale

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I use a 5 L pitcher, fiil with water (on Jul 3rd it was 25C/80F) and cool down with ice.
Developer and fixer are one shot with that cold water, and as I use it I keep adding water and ice to keep the temperature down.

 

[Maris]

I prefer film development well above 20C if it is conveniently available. Shorter developing times improve darkroom efficiency and throughput. And modern films are well hardened and don't care.

For sheet films one-at-a-time in a tray at a typical temperature of 30C allows my Xtol-rep developer to finish a sheet in 4 minutes. At 20C that would be more like 12 minutes a sheet which adds up to
a lot of black time (skull numbing) if I've got a dozen sheets of 8X10 to do.
Roll film goes through in 7 minutes at 25C with no problems. Other times, other temperatures follow the Ilford compensation chart remarkably closely. Thanks Ilford.

A regular warning against very short developing times is that uneven development may result. These precautionary techniques work for me:
Fully pre-soak the film in water before starting development.
Have all the solutions near the same temperature so there's no thermal shock.
Move the film in and out of the developer smoothly so there's no hesitation and the possibility of a "tide" mark. This comes easy after a little practice.

Tap water temperature can be remarkably constant. My water main is deep in the ground and it delivers at 23C all year round irrespective of the ambient air temperature.
I just have to run the darkroom tap a minute or two to flush away the hot/cold water from the surface pipes.

 

[dcy]

My cold tap water is hotter than 20°C ---- perhaps around 22°C or 23°C.

I've been putting the developer bottle inside a tray with water and ice cubes. I've found it quite difficult to control the temperature. I can get it within 1°C but the process is really slow and painful.

I might switch to the method where you adjust the development time based on temperature. I recently discovered Ilford's temperature compensation chart:

https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Temperature-compensation-chart.pdf

 

[koraks]

the temp is around 70 degrees and will keep the temp for the 5 minutes I need to wash film

Why would you need to wash film at 70F? It'll wash just fine (even more so) at a higher temperature.

 

[titrisol]

Why would you need to wash film at 70F? It'll wash just fine (even more so) at a higher temperature.

Thus, only developer needs to be at controlled temp, right?
fixing a couple of degrees warmer wont affect anything and getting reticulation by temp shock is very difficult

 

[koraks]

Thus, only developer needs to be at controlled temp, right?

Yes, correct. And even that can be time-adjusted to allow for temperature deviations within reasonable bounds (examples given in this thread go beyond those bounds).

 

[Paul Howell]

Why would you need to wash film at 70F? It'll wash just fine (even more so) at a higher temperature.

Out of habit, I keep my chemistry within a few degrees, left from the past when emulsions were soft and and a sudden jolt in temp could articulate the film or cause the grain to move about causing loss of sharpness. At least that was theory as presented by Kodak and taught in Air Force Tech School. I agree that developing film at say 70 degrees then washing at 80 will not cause any harm with modern films. The expection might be Double X movie stock which is an older emlusiton.