I'm looking for some practical advice on how to control the temperature of B&W developing and printing solutions. Where I used to live, I had the convenience of a concrete slab directly under my bathroom floor which kept my 5-gallon bucket of tempered water at a fairly constant 72 degrees. Now I have an upstairs apartment, and the ambient temperature varies wildly. I tried placing my beakers of working solution into trays of warm or cool water and stirring them, but my thermometer responds so slowly to temperature changes it's difficult to nail it down. Should I invest in a digital thermometer? Or am I approaching this entirely the wrong way?

Thanks...

Krum

-- Kevin Krumwiede (kjkrum@concentric.net), September 10, 2000

Answers

For printing, I don't worry about it. Whatever the ambient temperature is, that's my printing temperature. For film I got a big gray plastic dishpan like they use in restrarants. I fill this with water at whatever temp I want to process at. The chemistry goes in beakers that get quickly adjusted to temp in a pan of hot or cold water. Then they go in the dishpan. I also set the SS tank in the dishpan when I'm not agitating so the heat of my hand doesn't affect it. Any good dial or liquid thermometer should react within a few seconds to temperature changes- what are you using for a thermometer? I find the dishpan will hold temperature within about a degree for the ten to fifteen minutes it takes me to do a roll or two.

-- Conrad Hoffman (choffman@rpa.net), September 10, 2000.

A possible answer for your situation is to use Diafine for developing film. It is insensitive to temperatures between 70 and 85 degrees, as well as time and agitation variations. It is pretty fool proof.

For printing, the temperatures are not real important unless you have extreme temperature swings say over 80 degrees. If you know that the temperature only varies between 70 and 80 degrees, I wouldn't worry about print solution temperatures.

-- gene crumpler (nikonguy@worldnet.att.net), September 10, 2000.

Gene, I guess I should have mentioned that I am currently using 35mm TX and HC-110. (How quaint, I know...) I love the way TX looks and don't mind the grain since I rarely print anything larger than 5x7 for my album. I thought about using XTOL but nobody had any around, and I haven't come up with a compelling reason not to simply stick with what I know... since I don't know anything very well yet and probably wouldn't know the difference...

My thermometer is made by Kodak. It's an alcohol thermometer affixed to a paper scale and enclosed in a glass tube. The bulb of the thermometer is not in contact with the glass, but apparently insulated from the outside by the air in the tube. It didn't make a whole lot of sense to me when I bought it, but I figured hey, it's from Kodak! Waste of ten bucks.

Krum

-- Kevin Krumwiede (kjkrum@concentric.net), September 11, 2000.

Buy yourself one of those little digital thingies with a metal probe. I just got one from a market for #2 ($3US or so)! It's easier to read, faster reacting, and less breakable than my certified mercury/glass thermometer. They both read the same within +-1/4 degree.

Anyone want to buy a certified mercury thermometer for #10?

-- Pete Andrews (p.l.andrews@bham.ac.uk), September 11, 2000.

Krum, if you are using Tri-X and printing to only 5x7, I am not sure fussing about the thermometer will make any difference.

chris

-- Christian Harkness (chris.harkness@eudoramail.com), September 11, 2000.

Kodak makes better thermometers that are not too expensive. So does Jobo. Of course, you can buy them even cheaper used on eBay.

If you get a cheap digital, make sure you check it at the temps you are running. People seem to believe that since they read out to a tenth of a degree, they are accurate to that, NOT. You have to get up to the couple hundred dollar range to get accuracy in the degree range.

With Xtol at least (I just did some HP5+ in Xtol so I have the info handy) there is a significant difference in time from 70 to 72 degrees, so accuracy is fairly important.

One thing to watch with any wet (alcohol or mercury) thermometer, is that in shipping you may get separation in the liquid column. To fix, get a pan of very hot water, and carefully dip the bulb in and out to raise the column to the top. This will reconnect the liquid column.

I ran into this this weekend. Things didn't seem right, so I checked my one thermometer against my Kodak Process Thermometer (VERY accurate) and found a separated liquid column. A little hot water and it reads within about 1/2 degree of the process thermometer.

-- Terry Carraway (TCarraway@compuserve.com), September 11, 2000.

Whats been working for me lately is keeping a jug of distilled water in the fridge and then using that to mix with another jug at room temp. Don't know about your area but in mine I find used darkroom thermometers all the time under $10.00, sometime for as little as $3.00..

-- bill zelinski (willy226@yahoo.com), September 11, 2000.

Chris, you're right, but that's beside the point. :o) I want to develop a good working teqchnique so I'll be able to do things accurately when I start experimenting with less forgiving materials.

Thanks, everyone, for the advice. Sounds like I was right about needing a better thermometer.

-- Kevin Krumwiede (kjkrum@concentric.net), September 11, 2000.