Longevity of stock TF-5 Archival Rapid Fix?

[Greg]

Today I opened a gallon bottle of stock Photographers' Formulary TF-5 Archival Fixer to make a gallon bottle of working solution. The bottle is not dated by the manufacturer in any way. I do date bottles of chemistry when I get them, and this stock gallon bottle was dated 2018 by me. So I went to read the Product Instructions to double check its capacity and was surprised to read the following: "TF-5 stock solution should not be kept for more than 12 months". Mine is now 4 years old!!! but unopened. Mixed a gallon of working solution, and tested it, as I always do, for the clearing time of a piece of undeveloped film. Clearing time was as normal as when I tested the first bottle of working solution that I made from another stock bottle back in 2018. FYI: I do only use the working solution for no more than one year before mixing up a fresh batch.

Is the Product's Instruction sheet statement of "TF-5 stock solution should not be kept for more than 12 months" just being very over conservative as to the life of the stock solution? Would be interested in other member's experiences.

[Michael Wellman]

I had a similar experience with TF4 a couple of years ago. It was only 18 months old but worked fine. My only concern is that it's lifespan maybe shorter than normal with yours being 4 years old. I don't recall that being a problem with my TF4. I would use it and test every time prior to use.

[Renato Tonelli]

A friend of mine gave me some (still sealed) TF-5 purchased in 2017. I tested it and it still works fine.

[Tin Can]

I have a sealed TF5 gallon in my shed, temp varies from 10 to 110 F

The bottle is plastic, still clear looking like the day I got it 8 years ago

No loss of volume

Testing continues

A friend of mine gave me some (still sealed) TF-5 purchased in 2017. I tested it and it still works fine.

[esearing]

I'm on 4 years for a gallon jug partially filled and it still clears a leader in 20 seconds when diluted to working strength. Kept in garage that swings from 40-80+ degrees. I'd say it lasts longer than most people would use it up. Even diluted I have stretched its life to 6 months for film with infrequent use.

[Tin Can]

I have never seen TF5 slow down clearing a test strip

I replace it on a schedule

The only source I know is this

http://photoformulary.homestead.com/03-0200.pdf

[Doremus Scudder]

I'm on 4 years for a gallon jug partially filled and it still clears a leader in 20 seconds when diluted to working strength. Kept in garage that swings from 40-80+ degrees. I'd say it lasts longer than most people would use it up. Even diluted I have stretched its life to 6 months for film with infrequent use.

I suspect that the 12-month shelf-life given by PF for TF-5 is conservative. However, I'd be a bit uncomfortable keeping the stock solution for four years without more testing than a clearing-time test. It would be interesting if you used your old TF-5 on a fiber-base print or two and then did the ST-1 (or KRST) test for residual silver on it.

Ron Mowrey (PE) developed TF-5 and I suspect that the 12-month storage life caveat comes from him. Also, the recommendation to store smaller amounts of stock TF-5 in smaller bottles points to degradation due to oxidation. Maybe these recommendations are overly-cautious, but seeing some test results to really refute them would be reassuring

Best,

Doremus

[Michael R]

Ron was involved with TF-5 but he didn't write the instructions. The tech sheet is more or less a cut-and-paste from the TF-4 instructions and like most of the Formulary documentation is unfortunately a little long on marketing and short on useful. I agree the 12-month shelf life for the "stock" is likely conservative and not based on much. Ilford recommends 2 years for Rapid Fixer. One might expect TF-5 to be at least that since it is substantially a similar ammonium thiosulfate-based fixer at a less acidic pH. However we don't know (a) what additional ingredients are in TF-5 which might impact shelf life relative to a standard rapid fixer, (b) how TF-5 stock is prepared.

I suspect that the 12-month shelf-life given by PF for TF-5 is conservative. However, I'd be a bit uncomfortable keeping the stock solution for four years without more testing than a clearing-time test. It would be interesting if you used your old TF-5 on a fiber-base print or two and then did the ST-1 (or KRST) test for residual silver on it.

Ron Mowrey (PE) developed TF-5 and I suspect that the 12-month storage life caveat comes from him. Also, the recommendation to store smaller amounts of stock TF-5 in smaller bottles points to degradation due to oxidation. Maybe these recommendations are overly-cautious, but seeing some test results to really refute them would be reassuring

Best,

Doremus

[Drew Wiley]

Who knows. Maybe there's a point at which it settles out, and you need to stir it like unfresh jugs of TF4. I find it hard to believe it has to be used within six months, or even within a year.

[esearing]

I suspect that the 12-month shelf-life given by PF for TF-5 is conservative. However, I'd be a bit uncomfortable keeping the stock solution for four years without more testing than a clearing-time test. It would be interesting if you used your old TF-5 on a fiber-base print or two and then did the ST-1 (or KRST) test for residual silver on it.

Ron Mowrey (PE) developed TF-5 and I suspect that the 12-month storage life caveat comes from him. Also, the recommendation to store smaller amounts of stock TF-5 in smaller bottles points to degradation due to oxidation. Maybe these recommendations are overly-cautious, but seeing some test results to really refute them would be reassuring

Best,

Doremus

I use TF5 only for film with pyrocatM because it does not reduce the stain color - For paper I have always used small bottles of Ilford rapid fix because its what I can buy locally. I did try Wolfgang Moersch's Lobotype process and found that TF5 fixer gave me a grayer tone than TF4 or Hypo alone. For Salt prints TF4.

I did a residual test after the bottle had been open about 18 months. Maybe will try again next print session.