Freeze ferric oxalate solution?

[sanking]

A couple of months ago I mixed a rather large amount of ferric oxalate solution for kallitype and palladium printing, anticipating that I would use all of it within a relatively short period of time. Well, things happened and I was delayed in making the planned kallitype and palladium prints, and now I am going to be doing carbon printing only until July. Question is, can I keep the ferric oxalate solution (25%) fresh by freezing? Any literature on this?

Sandy

 

[EricNeilsen]

A couple of months ago I mixed a rather large amount of ferric oxalate solution for kallitype and palladium printing, anticipating that I would use all of it within a relatively short period of time. Well, things happened and I was delayed in making the planned kallitype and palladium prints, and now I am going to be doing carbon printing only until July. Question is, can I keep the ferric oxalate solution (25%) fresh by freezing? Any literature on this?

Sandy

Sandy, I have not seen anything about freezing it. It can be placed in cold storage to extend the ageing process, to slow the conversion down, but I have not seen if freezing will work. How about just the coldest part of the refrigerator? I'd add a little oxalic acid to it before I chilled it. It is relatively easy to make, I'd not worry too much about it but it would be fun to see. I have enough right now that I could throw it in the freezer just to see what happens.

Eric

 

[sanking]

Eric,

Thanks for your comments.

Well, I froze the FO solution, adding a little oxalic acid before as you suggested. I will pull it out in July and let you all know if it still works.

Sandy

Sandy, I have not seen anything about freezing it. It can be placed in cold storage to extend the ageing process, to slow the conversion down, but I have not seen if freezing will work. How about just the coldest part of the refrigerator? I'd add a little oxalic acid to it before I chilled it. It is relatively easy to make, I'd not worry too much about it but it would be fun to see. I have enough right now that I could throw it in the freezer just to see what happens.

Eric

 

[Gerald Koch]

It is not a good idea to freeze photographic solutions as some chemicals may crystallize out and become very difficult to get back into solution.

 

[EricNeilsen]

It is not a good idea to freeze photographic solutions as some chemicals may crystallize out and become very difficult to get back into solution.

Maybe true, but what in Ferric do you suppose will not go back?

 

[sanking]

Well, the answer appears to be that freezing a ferric oxalate solution does not negatively impact its working qualaties in Pt./Pd. printing. In early February I froze 150 ml of a 25% ferric oxalate solution. Well, I thawed it out yesterday and from what I can see the freezing did no harm at all. Granted, I did not do any before and after sensitometry tests so my finding is based merely on experience and eye-balling the results, but from what I can evaluate the thawed out ferric oxalate solution is giving results identical to a fresh solution I mixed about a month ago.

Sandy

 

[EricNeilsen]

THat's interesting. Did you find any precipatation in the bottle after the thaw?

Eric

 

[sanking]

THat's interesting. Did you find any precipatation in the bottle after the thaw?

Eric

Eric,

Absolutely none. The solution thawed out just as clear as it was right before I froze it, with no crystals or precipitate.

Sandy

 

[EricNeilsen]

Then I suppose the next question would be, Did anything else happen to it that might effect the aging of it and only time will tell. And since the volume represents and excess supply already, I doubt you have a plan to mix some more from the same batch of powder today to test that? Happy printing!