View Full Version : Effect of temperature on chemistry storage

15-Nov-2010, 11:32
I live in South Carolina. We can have temperature ranges from 20 degrees F in the winter to 120 degrees in the summer.

I am in the process of building a darkroom in a large shed on my property. The room will be about eight by sixteen feet in size. I will insulate the walls and ceiling, and have some form of portable heating and cooling for when I am using the darkroom. Most of the time, the darkroom will be impacted by the external temperature, since I do not plan to heat it or cool it while I am not using it.

Now, the question is this. What will be the impact on any chemistry I store in the darkroom? Will the chemistry die sooner than it normally would? Or, is it nothing to worry about?

I will keep my printing paper and film in the house, so that is not an issue. If I need to, I could do the same with the chemistry, but I would really not want to do this.

By the way, I am talking about not just B&W chemistry here, but also chemistry used for cyanotypes, van dyke brown, and in the future, carbon prints.

Gem Singer
15-Nov-2010, 11:48
From what I've been told over the years, just don't allow photo chemicals to freeze into ice, and they will be okay.

Assuming that they are properly stored in sealed containers, they should be capable of withstanding a wide range of temperature fluctuations.

Bob McCarthy
15-Nov-2010, 12:04
I would agree with that. To protect the plumbing. enlarger, etc. you may want to install some simple baseboard heating and leave the thermostat at 40-50 deg. or so. You can about store anything out there then. Just insulate it reasonably and the amount of energy consumption will be very small.


Lynn Jones
15-Nov-2010, 14:32
I mostly agree with the above, however, If the chemicals are fairly concentrated approaching "saturation" then refrigerator temperatures can precipitate some of the chemicals and usually they will not be re-dissolved even with relatively high temperatures. I have occasionally had this problem with full strength D76.


16-Nov-2010, 09:29
Thanks for the information. Since D76 is my favorite developer, I may have to rethink this. Maybe I could make a temperature controlled box to store my chemistry in. That way, I only have to heat and cool a small volume.

16-Nov-2010, 20:48
My darkroom is a walled-off portion of a flimsy building which originally served as a horse tackroom. The studs were ancient Douglas fir that were too hard to take drywall screws, so I furred them out and installed 5-1/2 inches of insulation. My assumption was that heavy insulation would make it practical to heat and cool the place when I wanted to work out there.

What I discovered was that a) it took a long time for the walls, equipment, and chemicals to warm up to a workable temperature, and b) my Dektol stock dropped out crystals (probably sulfite) that had to be redissolved by warming before I could do any printing. I was spending more time waiting for the place to be comfortable than I was working; trying to warm it up quickly resulted in dew on the enlarger (never a good thing...).

To my surprise, keeping it at about 65 F cost well under a dollar a day, once I found a thermostat with a small on/off differential, and I can pop in any time and be working in minutes.

If you are building from scratch, you could even do a floating interior wall and have even less heat loss; a few dollars more in original construction would give you a much nicer place to work.

Jim Noel
17-Nov-2010, 08:45
Liquid fixers will precipitate crystals at a fairly high temperature. Somewhere around 45 deg I believe. They are difficult to get back into solution.