Freezing developers

Has anyone here tried to freeze a developer to prevent oxidation?

No. I generally use mine up before oxidation concerns present themselves. Hmmm, I guess you could freeze a stock solution in measured amounts and add them to water that is slightly warmer than processing temp. giving you the correct dilution and temperature.

Thre's a big chance that chemicals will precipitate upon freezing. This is truer with concentrated devs.

Never freeze it. Only cool it up.

Jorge:

 

It depends on the solubility of each of the components at different temperatures.

 

Hans:

 

Minimizing the oxygen while storing photo chemicals is the key: Make sure your bottle caps seal tightly; and use propane from an unlit torch to displace the air. Also, use clean rocks or marbles in your jugs to minimize the air space atop the liquid.

 

EXCEPTION: Bleach, which likes oxygen -- In fact, bubbling air through it will extend its life.

 

I use screw top wine bottles (1.5l, 3l & 4l) to store my chemistry: As it turns out, wine connisseurs(!) have realized that modern crimped metal screw tops with PS (pulp-Saran) liners actually seal better than a cork does -- Either wet or dry.

propane in a glass bottle. wear dose the genius end

I have thought about this approach before and rejected it for the following reasons:

 

First, the salts in the solution will precipitate or come out of solution. They may also interact with each other during the freeezing process.

 

Second, as the solution cools, the oxygen concentration can actually increase as oxygen is more soluble in cold solutions than in warm solutions.

 

Finally, as the solution thaws, the least soluable components will form a "sludge" requiring agitation to get them back into solution. this can increase oxygenation leading to even more problems.

 

So, while I haven't tried the experiment, it seems to me that it would not be successful. I like the suggestion of a blanket gas that someone suggested earlier - although propane seems a little dangerous! I'd try nitrogen or some other fairly inert gas. Carbon dioxide is too soluble and will change the pH of the solution.

 

Hope these thoughts help.

Jim

 

Hope these thoughts help.

Dear Hans,

 

I don't know about freezing but a few months ago I was discussing chemicals stored at very low temperatures (around zero) with Ilford because some of my chemicals were stored in a barn during a move. They said that their concentrates will re-dissolve perfectly happily once the developer is re-warmed. I would imagine the same would apply to freezing but it's such an intriguing question I'll call them and ask them.

 

Cheers,

 

Roger

Hans

 

For many years I used Ilford concentrated syrup developers (LC 29??) and filled empty surplus plastic 35mm film containers to the brim, then put the caps on and put them in the freezer.

 

When I needed to use the stuff, I took one out and added it to 970 ml of water- the cans are almost exctly 30 ml- then diluted it for one time use. Worked great. I never noticed any precipitation with

the concentrated syrupy soup. It didn't freeze solid, just became a lot more viscous.

 

The concentration was just about exactly 31:1 as recommended. Anyway, it may have been off a bit but it still worked at my tested time/temps.

 

Cheers

An unintentional "experiment" of this nature (I forgot a small bottle of Unitol concentrate in the back of the fridge for several years) showed that some solids precipitated out and condensed very firmly on the inside of the bottle ... they didn't want to re-dissolve. The resultant liquid did still turn an exposed film snippet black, but I didn't bother to make any further tests.

 

My implications from this is that some dev's are certainly affected by long-term low-temperature storage, but I'd guess the dev would have deteriorated even sooner at room temperature.

 

I store all my liquid developers in the fridge ... each container is VERY clearly marked, and I do live alone, so have no problems with other people potentially mistaking them for lemonade or whatever.

Wally:

 

The propane isn't under pressure; plus, there's only a small puff (a few cc's) anyway.

 

Besides, propane is used as a propellant for aerosol dispensers...

You tell him Dan. That's 'wear' the genius 'dose' end.

Yep, propane is in everything aerosol these days. Butane is sold in flammable plastic packages called 'lighters'.

 

Freezing is probably the worst thing you could do for the reasons mentioned above. Propane is denser than air which means it would blanket the top of the solution. I question whether propane will mix with air, though, or any elements in the solutions. If it does, it's not helping the situation. Nitrogen is probably inert enough. Argon is completely inert. I use it because it's available. My darkroom at work is 100 ft. from a TIG welding room where there's lots of it. There is a commercial aerosol product sold to prevent oxidation and "skinning" on paint. I think it's called Bloxygen. I haven't tried it but I think if it's sold for this purpose it is denser than air and inert enough for our purposes.

Well argon is the best simply because it is completely inert and denser than air. Nitrogen is essentially inert to anything except a things in my lab (and certainly in a darkroom) and is infinitely more available to the average person. The real advantage of argon is the density but honestly if you bubble the N2 gas with a small enough exit, it will displace all the air anyhow. I guess some posts were deleted since I see no mention of propane but I can't say this would be my choice. Heaven help you if it ever lights off in the presence of any strong oxidants.

 

Carbon dioxide could be a bad idea. It is absorbed by basic solutions and will lower the pH.

Dust off also seems to work. I use it for E-6 and have never noticed a color shift. For black and white developers I don't use anything besides a full bottle.

Never tried freezing. In fact, you may have noticed I am currently going the opposite direction by pickling them in antifreeze. It works very well, too.