Using a "Silver-Saver" electrolytic system to re-vitalise film fixer -delusional?

[Smudger]

I play a small part in b/w film processing,on this small area of the globe. Currently using a 2-bath Tetenal Superfix fixing regime.

Any utility in keeping my first bath somewhat less silver-laden by a short treatment in the the Silver Magnet ,promoted here by jnanian ? Setup obtained elsewhere,so no connection to to the original seller.
pH around neutral, pre treatment.
Comments welcome.

 

[Mr Bill]

Hi, I'd guess it's hypothetically feasible, but probably not worth the effort.

There is a risk, I would guess, of forming some sulfide in the fixer, in which case you wouldn't want to use it anymore. Now, I'm doubtful that the Silver Magnet will produce sulfide provided that the silver concentration is above, say, 1 or 2 grams per liter, but this is just an educated guess. You would ideally know what the silver concentration is, via test paper or the like, and then determine how long to run the Magnet to get to a specific concentration. If you don't do it like this I think it's a risky thing to do because of possible sulfide formation.

A second thing is that most of the modern films will release iodide into the fixer, and this drastically slows down the rate of fixing with a thiosulfate fixer. So even if you could remove nearly all of the silver, the fixer might still have difficulty fixing. I was involved in an attempt to do something similar with C-41 fixer; we didn't try in-line desilvering, though. We collected overflow, then desilvered and "regenerated" the fixer, but in testing we concluded that the iodide issue made it not sensible. I want to be clear that I am talking about FILM, and not paper. For many years it was standard procedure in large labs to desilver bleach-fix (used for color paper) then regenerate it for reuse. So this is sort of evidence that it's doable for paper.

I really think, that for a small user, the extra work to desilver inline, even for paper, is not worth doing. At least not worth it financially - doing it just for fun is a different story. Best of luck with things.

 

[Smudger]

Hi, I'd guess it's hypothetically feasible, but probably not worth the effort.

There is a risk, I would guess, of forming some sulfide in the fixer, in which case you wouldn't want to use it anymore. Now, I'm doubtful that the Silver Magnet will produce sulfide provided that the silver concentration is above, say, 1 or 2 grams per liter, but this is just an educated guess. You would ideally know what the silver concentration is, via test paper or the like, and then determine how long to run the Magnet to get to a specific concentration. If you don't do it like this I think it's a risky thing to do because of possible sulfide formation.

A second thing is that most of the modern films will release iodide into the fixer, and this drastically slows down the rate of fixing with a thiosulfate fixer. So even if you could remove nearly all of the silver, the fixer might still have difficulty fixing. I was involved in an attempt to do something similar with C-41 fixer; we didn't try in-line desilvering, though. We collected overflow, then desilvered and "regenerated" the fixer, but in testing we concluded that the iodide issue made it not sensible. I want to be clear that I am talking about FILM, and not paper. For many years it was standard procedure in large labs to desilver bleach-fix (used for color paper) then regenerate it for reuse. So this is sort of evidence that it's doable for paper.

I really think, that for a small user, the extra work to desilver inline, even for paper, is not worth doing. At least not worth it financially - doing it just for fun is a different story. Best of luck with things.

Well, it is more along the lines of "fun" ,but the plan of extending the life of fixer was more my intent. And to those who are tempted to reply "Fixer is cheap, forget about it" -they tend to live in First-world countries where this statement may be valid.Where I live,it ain't.

 

[AgX]

But still using a two-stage fixing process, with running the first bath to a state where it is overloaded compared to a one-stage process, then substituting the first by the second one and then desilvering the first bath, without using it any further, makes sense to me.
Especially as at average the final bath is in better state than in the single-step process.

Whether desilvering with amateur means makes sense economically is something different.
Some may do it as they got no practical chance to deliver it in for proper ecological treatment.

 

[georgegrosu]

I worked for years in film processing cine laboratories.
Prints films (b&w and color) reuse fixer solutions is current made.
Electrolyzed of fixer solution recovered, did the addition of chemicals and then use regenerated fixer in process.
A fixer solution could not reuse indefinitely.
The fixer solutions we had in closed circuit with a basin about 500 l buffer down.
When I saw that the buffer the fixer solution basin comes it foams
Make fresh fixer.
I worked at the negative all the time with fresh fixer solution.
From the fixer solutions, recover electrolytic silver about 2 tons / year (2 laboratories).

George

 

[Doremus Scudder]

I imagine you'll save more time and money by simply using the first bath to close to exhaustion and then recovering the silver from it before discarding.

Best,

Doremus

 

[Neal]

Dear Smudger,

I have done exactly what you are asking using a "Silver Magnet". As noted above, it doesn't work forever. My practical suggestion is one re-use followed by a second silver removal before disposal. The test strips (the paper ones are good enough) will tell you when sufficient silver has been removed.

Good luck,

Neal Wydra

 

[RalphLambrecht]

But still using a two-stage fixing process, with running the first bath to a state where it is overloaded compared to a one-stage process, then substituting the first by the second one and then desilvering the first bath, without using it any further, makes sense to me.
Especially as at average the final bath is in better state than in the single-step process.

Whether desilvering with amateur means makes sense economically is something different.
Some may do it as they got no practical chance to deliver it in for proper ecological treatment.

agreed 100%

 

[Gerald C Koch]

LFA Mason Photographic Processing Chemistry discusses this in the chapter on fixation. At one time this was done by large film processors. The problem is not only the buildup of silver in the fixer but also other chemicals such as bromide and iodides. Iodide has become a problem with T-grain and Delta films. Iodide ion can be removed by the addition of a thallium salt to the solution whereupon insoluble thallium iodide precipitates. However thallium salts are EXTREMELY POISONOUS. For the home enthusiast attempting to reclaim fixer for continued use if just not practical.