Water temperature control unit
I need your help. What options do I have to control water temperature, to maintain at 20C? I live in Los Angeles and have lots of problem with water temperature.
There is the time-honored method of turning on the cold water to get the flow you want and then turning on the hot water just a trickle to bring up temperature.
There are thermo-mechanical mixing valves which you set to the temperature you want and the unit controls hot and cold proportions to maintain the temperature you set. These tend to require a great flow of water to really work well. (Leonard / Leedal are a couple brands). I use a Leonard valve.
Then there are the electronic temperature control valves that are a bit expensive, but well-loved (Hass Intellifaucet).
When the cold water is already 70-degrees F, then the easiest solution is to have some ice cubes in plastic bags. (Tray processing prints - works to get the tray down to 68-degrees F in a few minutes). For summer processing, I literally have a coiled cold-water hose that I submerge in an ice chest on the way to the darkroom sink. At a low flow I can have water at slightly above 70-degrees down to exactly 68-degrees.
There are lots of options, but unless you are running your cold line through a water chiller, you will be limited to the ambient cold temperature that comes out of your faucet. I grew up in the greater Los Angeles/Orange County area (with darkrooms in Anaheim and Cypress) and never had cold water temps lower than the mid-70s F in winter. And up to the low-80s F in summer.
DIY chillers are possible. Coiled copper tubing inside large ice chests, for example. Or (expensive) commercial units. These would be for running water options.
For static control your best bet would probably be a water bath, the bigger the better, chilled down manually with water ice, dry ice, or artificial freezer ice packs. This was my solution when I lived in the area. Those busboy cart dish containers are large and work well.
And welcome to APUG...
Last edited by Ken Nadvornick; 11-30-2013 at 09:25 PM. Click to view previous post history.
Reason: Updated info...
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A few years ago I bought a Delta 1 temp gage for the faucet. http://www.bhphotovideo.com/c/produc...p_II_with.html
It was simple and it is all I need to get the temp correct. $70 beats those $$$ regulators for most things I need.
Get it right in the camera, the first time... My flickr
Check your cold water temp and see if you need cooling. Many south west locations need to drop the temp for standard developers.. If not under what you need the garden hose in teh big cooler full of ice is much cheaper than commercial refridgeration. There is a temperature control valve for sale on Large Format forum for $50, might be a good buy.
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You can make those from parts found at a hardware store for $25-$30.
Originally Posted by mrred
I promise you--you don't have any more problems with water temp in LA than the rest of us. It's a constant battle,and no thread on the internet is going to cure that. You'd probably waste less time reading War and Peace and get an equal amount of help out of it. It's strictly ingenuity and junk-on-hand. Like making a fighter jet out of a slingshot and a piece of paper.
Originally Posted by Huck
Keep a good supply of ice cubes in the freezer and add as many as you need to a water bath in which you have placed your developer. The highest temperatures out of the cold tap which I have to deal with are about 28 C.
What is the water to be used for, meaning how much of it is needed? If you are running a large automated machine needing water at 20C then the problem is very different to needing a couple of litres for processing a roll of film...
To adjust tray temperature at the setup of a print session might be most easily done with (clean) ice cubes when mixing the chemicals, but it would then start to warm up so airco in the darkroom might be an option. Or put the tray inside a larger one on the bain-marie principal, but this interferes with agitation and requires constant attention. There are also chemical formulae for 'tropical' developers etc. (for use in very high temperature environments) which could be home made.
It is not necessary to have exactly 20°C for film or paper developing. As long as the water temperature is not so high as to damage the emulsion, you can just process at the existing cold-water temperature, making sure, of course, that you compensate for the increasing in developer activity by reducing the developing time appropriately.
See here http://www.ilfordphoto.com/Webfiles/...0208211880.pdf for the Ilford time/temperature compensation chart.
I have no problems developing film at 24°C or even slightly higher in the summer. For prints, it is even easier, since the leeway is a lot more.
Water cooling is really only necessary when the temperatures are up around 27°C/80°F or higher. Even then, many films will develop just fine with no damage. If your water is really hot, check out additives and special developers for tropical processing.