Frozen Fixer

Mixed a gallon of fixer and placed in the freezer with a gallon of

D76. The D76 is frozen hard, the fixer is mushy. Anybody know what

the freezing point of Kodak fixer is?

ummmmm....I've been developing B&W for 30 years, and I've never heard of freezing your chemicals. Of course, I use one shot developers, or treat them like one shots...and treat the fixer like a 2 or 3 session fixer.........than chuck it all. It ain't THAT expensive. Are you sure freezing is a recommended procedure?

Freezing chemicals is not a good idea. Stock solutions are pretty concentrated, and chilling may cause precipitation of components that may be difficult, or impossible, to re-dissolve when you warm the solution again.

I'm not sure that is a good idea. Most chemicals have a specific range for temperatures for storage. I can't be sure with this specific chemical compound, but I have read in multiple places posts from people who have had precipitation problem that could not later be re-disolved. I would think that storing the powder would be a much better idea - less space, less chance of problems, etc..

 

- Randy

I was mixing up small usage quantities from the large bulk dry powder Kodak packages. Read where the individual dry chemicals could/would seperate and concentrate, making the proper dry ratios invalid for correct mixing even after vigorous shaking. So... I mixed an entire package and froze the containers to see what happens. Noticed the extremely long time for the fixer to freeze, interesting.

 

Haven't tried thawing and using yet but will soon. This has to be easier than digital, right?

 

Thanks for the help and warnings.

 

Regards.

There's a "freezing point depression constant" based on the osmolality of the solution that

i vaguely remember from chemistry studies. That's about it. That would enable you to

determine by how much a given concentration of a given solution would depress water's

freezing point below 0 celsius.

 

Maybe google to the rescue here? perhaps Kodak would know the osmolality of the

solution or even its freezing point?

 

Good luck,

 

Mike

Hi Michael S, thanks for the tip, did a Google, don't think the freezing point of fixer is THAT interesting or important now. WHEW, where do all the "moles" go when things are working right? GRIN.

 

When the stuff thaws I'll see if I can get everything dissolved again.

 

Regards.

I freeze my E-6 1st & color dev working solutions, as well as C-41 replenisher, all with no ill effect. But remember, these work at 100F, not room temp.

 

When you defrost the D-76, take it back up to 120F, which is where you mixed it at.

Hi Dan, thanks for the tips. I'll be doing some film tonight or tomorrow and then should know how my stuff goes through the freeze/thaw cycle. Regards.

John:

Ive been mixing my chemistry in small batches from powder for just over 6 months now. No problems here, yet. Futhermore I posted on this forum asking if anyone had had a first hand problem mixing small batches of powdered chemistry and no one responded that they had. I did get several posts describing possible problems from unmixed chemistry in the bag of powder. But still no one posted that they themselves had experienced the problem.

Good luck with your freezing. I hope your jugs don't split from the expansion of freezing water. (If youre wondering; No, MY frozen photo chemistry has never split its containers in my freezer. ;-})

Hi Lee, thanks for the info. If freezing works it will be less trouble for me.

 

I developed some film last night using the frozen chemicals; and, everything worked OK after thawing and then heating/restirring the D76 at around 120F, the fixer was clear after thawing. Hope everything works for another 8 cycles. Those old plastic milk jugs seem to withstand the freeze/thaw cycle ok.

 

Dan, I think I'll try some E6 after hearing your success freezing the chemicals. Need to get a tank though, don't think tray development is healthy using color chems.

 

Regards.

Never tried freezing chemicals but have often considered it for working solutions (why do you need to freeze stock solutions?!)

 

The reaction rate of chemicals is proportional to the square of the temperature, so if cooling your chemicals even a few degrees C, you're already doing well to increase their longetivity.

 

Being water-based inorganic chemicals, the only worry about freezing is the expansion of water and the crystallisation. To obtain a fully working solution again you have to re-dissolve it properly. This is a physical process, the chemistry of the solution remains the same.

"Never tried freezing chemicals but have often considered it for working solutions (why do you need to freeze stock solutions?!)"

 

Hi Chris, thanks for the info. "Freeze it and forget it" is my reason. Mixing one large batch as opposed to smaller amounts saves me time. Air/chemicals and low temperature is better than air/chemicals and high temperature as you indicated. Regards