keeping fixer

[ian the framer]

Being new here I suspect this has probably been covered before, so please point me to a previous thread if so, but I am confused about storing fixer

I know that I can test fixer with strips to measure the silver content, and therefore tell if it is exhausted, but if kept in a bottle (mixed) does it “go off” and how can you tell? Does the Ph change or is there a visible indication?

Ian

 

[bsdunek]

Fixer seems to last a long time for me, as much as a year. I try a piece of exposed film to assure that it clears, and also have the test liqued that indicates if it is over used. Other wise, I use it until it doesn't test good.

 

[wclark5179]

I keep fixer, after thorough washing, in used up spaghetti sauce jars. It's a brand from Italy that I can buy here in Minnesota. The cap covers the entire width of the jar! Easy to pour out to the tray/tank and easy to get back into the jar. I throw the working solution fixer out after each printing session (I store up enough work to print to exhaust the fixer, especially when I use fiber based paper. Film fixer I throw away as it takes more time to clear the film.) I store the jars with working fixer under the sink cabinet. I used either Ilford Hypam or Rapid fix.

 

[tkamiya]

i use Kodak Professional Fixer. Although the package instructions says it keeps for 6 months in sealed bottle without air, it lasts well over 6 months for me. My last batch lasted 8+ months. Its degradation seems to have more to do with usage count rather than age.

For testing its vitality, I save film leaders that I cut and use that as a test clip. Soak it in the fixer in question and time how long it takes to clear. Tmax film seems to clear in 4 minutes or so when fresh and as it ages, it takes as long as 6 minutes and at that point, I discard it and mix a fresh batch.

Other than general junk floating in the liquid, there is no visible indicator when it gets old. I have no ways to measure PH so I don't know the answer to that either. My general rule is, test (as indicated above) when it passes manufacturer's specified storage period.

 

[ian the framer]

Thank you

Is the film clip test relevant to fixers used for paper?

Ian

 

[bsdunek]

Thank you

Is the film clip test relevant to fixers used for paper?

Ian

That's how I do it. It seems to work fine. tkamiya seems to concur. I find about the same clearing times as he does.

 

[tkamiya]

While fully understanding the needs for film clearing and paper clearing is not the same, film clip test still confirms for me that the fixer has not gone completely flat. I can also judge from clearing time, how bad/good the solution is. Since paper does not look any different fixed or not fixed, and I do not have any other ways to test my fixer, that is the way I do it.

More importantly though, I keep a record of how many 8x10 the paper fixer has processed on the bottle and discard it when it reaches or gets close to the maximum number. Conveniently, for me, 6 to 8 months and maximum number usually happens at about the same time. By then, there is enough "junk" (lint and such) floating around, I would not want to keep it any longer anyway.

Enjoy your darkroom work!!

 

[RobertV]

For film and PE/RC papers the limit is 2g/ltr. Ag+ ions satturation in the fixer. You can test this with a Potassium Iodide (KI) solution, also known as fixer tester.

10ml fixer + a few drops (5) of tester if it stays clear the fixer limit is not reached yet. If it stays milkey you're over the limit.
But when making a film fix you can also count how many films were fixed. However T grain type films take more capacity of your fixer. Here you have about 60% left of the total capacity.

 

[Mike Wilde]

The other indicator is to look for a yellow/white crud that smells strongly of sulfur that sticks to the bottom of the storage container.

The remaining liqiud may still have limited fixing capacity, but the sulfur also is in microscopic specs that will stick to your film/print so it is safer to call it dead once it begins to sulfate out.

 

[Ian Grant]

For film and PE/RC papers the limit is 2g/ltr. Ag+ ions satturation in the fixer. You can test this with a Potassium Iodide (KI) solution, also known as fixer tester.

10ml fixer + a few drops (5) of tester if it stays clear the fixer limit is not reached yet. If it stays milkey you're over the limit.
But when making a film fix you can also count how many films were fixed. However T grain type films take more capacity of your fixer. Here you have about 60% left of the total capacity.

Your out by rather a long way, the limit is closer to 8-10gms per litre with no long term adverse effects for films.

For FB papers the limit is 2gm/litre. RC/PE papers are between the two at 4-6 gm/litre

Ian

 

[RalphLambrecht]

Your out by rather a long way, the limit is closer to 8-10gms per litre with no long term adverse effects for films.

For FB papers the limit is 2gm/litre. RC/PE papers are between the two at 4-6 gm/litre

Ian

That's a bit too liberal for me.

We must make a difference between 'commercial' and 'archival' processing and also consider the differences between one and two-bath fixation. As far as I know, the most reliable research on this subject was conducted by Grant Haist (Director of Research at Kodak) and Dr. Michael J. Gudzinowicz (Rochester Institute of Technology). Here is an excerpt of his paper 'Post Development Processing'. With a bit of luck, you'll find a copy on the internet somewhere.

More on Fixing - One and Two Bath Fixation
Grant Haist, the former director of research at Kodak, cites the following maximal permissible values for one-bath film and paper fixers for commercial and archival processing:

One-bath fixation: Commercial Archival

Film:
Max. Ag conc.: 1.5 g/l 0.2 g/l
Max rolls/gal: 25 rolls/gal 2 rolls/gal
Non-image Ag in film: 0.01 mg/in^2 0

Paper:
Max. Ag conc.: 0.3 g/l 0.05 g/l
Max. sheets/gal: 30 8x10 5 8x10
Non-image Ag in paper: 0.005 mg/in^2 0

Essentially, as fixer total silver (free and complexed) and halide concentrations rise, the fixer's ability to remove all of the silver from the paper diminishes markedly, as indicated by the very limited capacity of one-bath to remove silver to archival levels.
The solution to the limited capacity is to use a fresh second fixer bath to maintain a very low total silver level, with a water rinse between the first and second baths to minimize fixer/silver carry-over. Some older texts even suggest a fresh third bath.

Two bath fixation: Commercial Archival

Film:
Bath 1:
Max. Ag conc.: 6 g/l 3.5 g/l
Max. rolls/gal: 60-70 40
Bath 2:
Max. Ag conc.: 0.5-1.5 g/l 0.02 g/l
after 60-70 after 40
Non-image Ag in film: 0.01 mg/in^2 0

Paper:
Bath 1:
Max. Ag conc.: 2 g/l 0.8 g/l
Max. sheets/gal: 200 8x10 70 8x10
Bath 2:
Max. Ag conc.: 0.3 g/l 0.05 g/l
after 200 after 70
Non-image Ag in paper: 0.005 mg/in^2 0

The first fixer gets rid of most of the silver, and the second maintains a very low silver concentration and relatively high free thiosulfate concentration to remove the remainder of the insoluble complexes and non-image silver present in the emulsion after the first fixation.
The first bath is used for the maximum number of sheets or rolls indicated, and then discarded after silver recovery.
The second bath is substituted for the first, and a fresh second bath is prepared.
After 5 cycles (substitutions), or one week if continuously exposed to air in tanks, both baths are replaced. Compare the capacity for commercial or archival standards using two baths to that for one. Two bath fixation is far more economical than using one bath, and avoids the temptation to over-use fixer which results in under-fixation and difficult removal of insoluble complexes which destroy prints and film.

Consequently, I recommend two-bath fixing and a 1st-bath limit of 3 g/l for film, 2 g/l for RC and 0.5-1.0 g/l for FB.

 

[Ian Grant]

We balance theoretical optimals with realistic realities.

Haist didn't do any of this research, the Kodak work was done at Harrow by G.I.P. Levenson, using Sodium Thiosulphate based fixers, later Ilford work was with Ammonium Thiosulphate fixers.

Haist is referring to Sodium Thiosulphate fixers, we now mostly use Ammonium Thiosulphate fixers which are quite different, there's a very long slanging post on Photonet on this issue where neither side realised both were right because they were referring to very different types of fixer.

Ian

 

[RalphLambrecht]

We balance theoretical optimals with realistic realities.

Haist didn't do any of this research, the Kodak work was done at Harrow by G.I.P. Levenson, using Sodium Thiosulphate based fixers, later Ilford work was with Ammonium Thiosulphate fixers.

Haist is referring to Sodium Thiosulphate fixers, we now mostly use Ammonium Thiosulphate fixers which are quite different, there's a very long slanging post on Photonet on this issue where neither side realised both were right because they were referring to very different types of fixer.

Ian

Ian

That is correct, but in your post (#10) you told Robert that he was way off, and suggested different numbers, but you never specified sodium or ammonium thiosulfate or asked for his fixer assumption. With general target values, one must assume worst-case conditions, and in this case, that is sodium thiosulfate.

In any event, I would stick to the values suggested by Haist.
Better to be safe than sorry.

 

[RobertV]

Consequently, I recommend two-bath fixing and a 1st-bath limit of 3 g/l for film, 2 g/l for RC and 0.5-1.0 g/l for FB.

Well I did all my photo life on 2g/l testing kit of KI for PE/RC and film. Indeed for fiber paper it's more critical and I can only recommend the 2 bath fixing method.

Not way off, just a practical and safe limit and easy to check.

 

[2F/2F]

That's a bit too liberal for me.

We must make a difference between 'commercial' and 'archival' processing and also consider the differences between one and two-bath fixation. As far as I know, the most reliable research on this subject was conducted by Grant Haist (Director of Research at Kodak) and Dr. Michael J. Gudzinowicz (Rochester Institute of Technology). Here is an excerpt of his paper 'Post Development Processing'. With a bit of luck, you'll find a copy on the internet somewhere.

More on Fixing - One and Two Bath Fixation
Grant Haist, the former director of research at Kodak, cites the following maximal permissible values for one-bath film and paper fixers for commercial and archival processing:

One-bath fixation: Commercial Archival

Film:
Max. Ag conc.: 1.5 g/l 0.2 g/l
Max rolls/gal: 25 rolls/gal 2 rolls/gal
Non-image Ag in film: 0.01 mg/in^2 0

Paper:
Max. Ag conc.: 0.3 g/l 0.05 g/l
Max. sheets/gal: 30 8x10 5 8x10
Non-image Ag in paper: 0.005 mg/in^2 0

Essentially, as fixer total silver (free and complexed) and halide concentrations rise, the fixer's ability to remove all of the silver from the paper diminishes markedly, as indicated by the very limited capacity of one-bath to remove silver to archival levels.
The solution to the limited capacity is to use a fresh second fixer bath to maintain a very low total silver level, with a water rinse between the first and second baths to minimize fixer/silver carry-over. Some older texts even suggest a fresh third bath.

Two bath fixation: Commercial Archival

Film:
Bath 1:
Max. Ag conc.: 6 g/l 3.5 g/l
Max. rolls/gal: 60-70 40
Bath 2:
Max. Ag conc.: 0.5-1.5 g/l 0.02 g/l
after 60-70 after 40
Non-image Ag in film: 0.01 mg/in^2 0

Paper:
Bath 1:
Max. Ag conc.: 2 g/l 0.8 g/l
Max. sheets/gal: 200 8x10 70 8x10
Bath 2:
Max. Ag conc.: 0.3 g/l 0.05 g/l
after 200 after 70
Non-image Ag in paper: 0.005 mg/in^2 0

The first fixer gets rid of most of the silver, and the second maintains a very low silver concentration and relatively high free thiosulfate concentration to remove the remainder of the insoluble complexes and non-image silver present in the emulsion after the first fixation.
The first bath is used for the maximum number of sheets or rolls indicated, and then discarded after silver recovery.
The second bath is substituted for the first, and a fresh second bath is prepared.
After 5 cycles (substitutions), or one week if continuously exposed to air in tanks, both baths are replaced. Compare the capacity for commercial or archival standards using two baths to that for one. Two bath fixation is far more economical than using one bath, and avoids the temptation to over-use fixer which results in under-fixation and difficult removal of insoluble complexes which destroy prints and film.

Consequently, I recommend two-bath fixing and a 1st-bath limit of 3 g/l for film, 2 g/l for RC and 0.5-1.0 g/l for FB.

This is why I have started doing double-concentrated two bath fixing with film and paper. Not only does it let you use your first bath longer (due to less time in it and twice the capacity), but it is also more archival. I do twice the clearing time in each bath, which is usually about three to four minutes total. I use a two minute rinse in between fixer baths.

 

[Ian Grant]

Ian

That is correct, but in your post (#10) you told Robert that he was way off, and suggested different numbers, but you never specified sodium or ammonium thiosulfate or asked for his fixer assumption. With general target values, one must assume worst-case conditions, and in this case, that is sodium thiosulfate.

In any event, I would stick to the values suggested by Haist.
Better to be safe than sorry.

The figures I gave were Ilford's for Hypam & Ilford Rapid fixer. Hypam's been in production for over 50 years so there's plenty of data on negative & print stability.

Mason & Levenson say film fixer shouldn't exceed 15 gm/litre and 8-10gm/litre is more usual.

For papers they suggest the max 2g/litre limit (only FB at the time of writing) and lower for best archival permanence.

That mirrors Ilford's current recommendations very closely, with a 0.5 gm/litre silver content for archival processing. Two bath fixing of FB prints is an easy way to keep below that limit

The issue is unstable silver/thioulphate complexes bonding with cellulose in FB papers, films and RC papers can tolerate very much higher silver levels in fixer as the complexes are far easier to wash out of the emulsion.

Ian

 

[RalphLambrecht]

Ian

Except for the film values, it doesn't look that we're all that far apart anymore. If one develops film two-bath one-shot, silver concentration in fixer is not an issue for the film processing procedure.

By the way (just to be picky again):

The SI unit abbreviation for 'gram' or 'grams' is a single lower-case 'g'. You have used three different abbreviations in your posts so far (g, gm and gms). That can cause confusion in some cases. As I said, picky.

 

[Ian Grant]

Ian

Except for the film values, it doesn't look that we're all that far apart anymore. If one develops film two-bath one-shot, silver concentration in fixer is not an issue for the film processing procedure.

By the way (just to be picky again):

The SI unit abbreviation for 'gram' or 'grams' is a single lower-case 'g'. You have used three different abbreviations in your posts so far (g, gm and gms). That can cause confusion in some cases. As I said, picky.

Picky

Unfortunately others over the years use various abbreviations g gm gm. gram gramme(s) etc, I've been OCR'ing some older articles etc and get used to keeping the abbreviation as in the original. So it depends whose figures I've used & what I've just been checking

Mason uses gms, Ilford & Agfa g, Kodak & Ansco grams & others gm. Luckily none can be confused with any other unit, gr is always grains.

Ian

 

[RalphLambrecht]

http://en.wikipedia.org/wiki/International_System_of_Units

 

[Bob Carnie]

I always use a two bath fix for prints, depending upon amount of prints I will put the second bath to the first and put the first bath into the silver recovery machine.

 

[RalphLambrecht]

I always use a two bath fix for prints, ...

Works well for films too.

 

[Bob Carnie]

We use single shot fix , so always one fix for film , never thought double was needed.

Works well for films too.

 

[RalphLambrecht]

We use single shot fix , so always one fix for film , never thought double was needed.

During the fixing process, the residual silver halides are dissolved by thiosulfate without any damage to the metallic silver forming the image. The resulting soluble silver thiosulfate and its complexes increasingly contaminate the fixing bath until it no longer dissolves all silver halides. Eventually, the solution is saturated to a point at which the capacity limit of the fixer is reached. The fresher, second bath ensures that any remaining silver halides and all insoluble silver thiosulfate complexes are rendered soluble.

Having said that, when already using fixer one-shot, a second bath is more important for rotation processing where less fixer solution promotes fixer exhaustion.

 

[Bob Carnie]

Ralph
I am using 1000ml per jobo run of fresh fix, is it possible I would need the second fix?

During the fixing process, the residual silver halides are dissolved by thiosulfate without any damage to the metallic silver forming the image. The resulting soluble silver thiosulfate and its complexes increasingly contaminate the fixing bath until it no longer dissolves all silver halides. Eventually, the solution is saturated to a point at which the capacity limit of the fixer is reached. The fresher, second bath ensures that any remaining silver halides and all insoluble silver thiosulfate complexes are rendered soluble.

Having said that, when already using fixer one-shot, a second bath is more important for rotation processing where less fixer solution promotes fixer exhaustion.

 

[Ian Grant]

Highly unlikely.

When Ilford published replenisher research back in the mid 50's about 1 g of silver gets created during development of 12 120 films, roughly the same amount of silver ends up in the fixer. Modern films contain less silver, some like Tmax much less.

As the recommended max limit is 8-10 g per litre for films per litre of Hypam or equivalent at 1+4 that 1 litre can easily safely fix far more films than your Jobo can probably hold. At 1+9 the number halves. However other issues come into play because of higher Iodide levels with some modern films and Ilford actually recommend 24 films per litre @ 1+4 which in practice is less than 2 g/litre silver with modern films so well inside the maximum recommended levels.

We used to collect X-ray film & fixer for silver recovery, very thick double sided emulsions and the fixer silver level was often 12-15 g/litre silver, after over 7 years there was never an issue. (In the UK hospitals etc have to keep processed Xray film a minimum of 7 years by law).

Somewhere in the UK I have the silver content of most types of films & papers in g/sq metre, colour & B&W. The recoverable silver was quite close to the theoretical.

Ian