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.

[Doremus Scudder]

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.

I don't know about Pyrocat, but using Ilford Rapid Fixer or Hypam with PMK negatives has no influence on the stain (despite the PF instruction sheet - I guess Michael that you're correct about the unreliability of the PF instructions...). I've use TF-4 with PMK negs as well as Kodak and Ilford rapid fixers and saw no difference in stain formation.

That's not to say you shouldn't use TF-5, just that, maybe, the notion that more acidic fixers affect Pyrocat stain is false.

Best,

Doremus

[motocbiker]

Does anyway have or know where to locate the formula for TF4 & TF5?

My inital earches have come up empty handed.

Thanks very much.

[Michael R]

They are proprietary so you will not find them. They are not magical - essentially ammonium thiosulfate-based, like any standard rapid fixer, but with some additional compounds not disclosed. TF-4 is alkaline. TF-5 is neutral (preferred) and was formulated with the assistance of Ron Mowrey (former Kodak emulsion engineer) who incidentally designed various novel fixer formulas of his own (one of which can be home-mixed), although TF-5 is more conventional. Kodak's Flexicolor fixer is similar.

If you want to home-mix a neutral rapid fix, it is quite trivial. Ryuji Suzuki's formula is as good as anything out there:

500ml water
Ammonium thiosulfate (120g or 200ml of the more commonly available ~60% solution)
15g sodium sulfite (anhydrous)
5g sodium metabisulfite
+water to make 1l working solution target pH approx. 7

Reducing the metabisulfite/bisulfite will increase pH (ie makes it alkaline).




Does anyway have or know where to locate the formula for TF4 & TF5?

My inital earches have come up empty handed.

Thanks very much.

[Tin Can]

I find TF5 mixed as recomened lasts very long

USE known distilled water

So long it seems to not diminish

It's MAGIC!

I buy 4 gallons at a time as shipping is best at that weight

If you have not tried it...

What do you know?

[Michael R]

It lasts long mostly because thiosulfate is much slower to decompose under a neutral/alkaline condition than an acidic one. Or it is because of magic. Whichever makes one feel better.

[Tin Can]

So you have not tried it…



It lasts long mostly because thiosulfate is much slower to decompose under a neutral/alkaline condition than an acidic one. Or it is because of magic. Whichever makes one feel better.

[paulbarden]

Does anyway have or know where to locate the formula for TF4 & TF5?

My inital earches have come up empty handed.

Thanks very much.

As stated, the recipe is proprietary to Photographer's Formulary, so you won't find it. The Ryuji Suzuki's formula is a good alternative with very similar traits.

[Michael R]

So you have not tried it…

LOL I did try a bottle of it a long time ago. It worked fine but nothing magical happened :(

I haven't looked at the prices in a while but at the time it was expensive compared with Ilford Rapid Fixer, so I went back to the Ilford product. TF-5 might make more sense for someone who needs a fixer to keep a longer time, but it wasn't worth it for me. Neutral fixers like TF-5 also have less odour, which is nice, but there are other ~neutral rapid fixers just as good. Sprint is an example.

It's too bad Ron never got to publish or commercialize the last iterations of his Superfixers (I think VIII was the most recent - it would fix in seconds, wash out of FB in less than a minute, and was apparently less nasty than Superfix I).

[Sal Santamaura]

...TF-5 is neutral (preferred)...

Preferred why?

[Tin Can]

I consider all analog photography Alchemy

AKA MAGIC

THAT IS EXACTLY HOW I SAW IT AGE 7

long ago with minox

[Michael R]

Preferred why?

No earth shattering reasons. TF-5 is a little more convenient to mix into working solutions than TF-4 which has the gunk. And being close to neutral in pH means less odor for those who are bothered by either the usual acrid smell of acid fixers* or the ammonia smell typical of alkaline fixers. Other than that they do the same thing.

*As an example, for people sensitive to the smell of acidic fixers, Kodak recommended mixing a less acidic version of F-5 called F-6 in which the boric acid is omitted and sodium metaborate is added to raise the pH.

[Tin Can]

Art may use 'science' but science is not art

I am so happy I quit Physics age 21

and did not waste my life with all the shit they just denied

String Theory, Big Bang, on and on

I worked in Labs on applied science almost my entire life




I really did not want to help make better bombs

I knew how to make a nuke age 8 from the Library

[Michael R]

The obligatory “science is not art” mic drop. The last refuge of anyone who is neither artist nor scientist.

[Drew Wiley]

I recently switched over to TF5. It seems to be a worthy replacement to TF4 in every respect, but is actually a little cheaper, and it doesn't need to be aggressively stirred if the bottle has been laying around awhile. TF4 lasted quite well in concentrate. But I'll use my TF5 too soon to give a long-term answer about its storage life. No difference between them with respect to PMK pyro stain results.

[Sal Santamaura]

Preferred why?


No earth shattering reasons. TF-5 is a little more convenient to mix into working solutions than TF-4 which has the gunk. And being close to neutral in pH means less odor for those who are bothered by either the usual acrid smell of acid fixers* or the ammonia smell typical of alkaline fixers. Other than that they do the same thing.

*As an example, for people sensitive to the smell of acidic fixers, Kodak recommended mixing a less acidic version of F-5 called F-6 in which the boric acid is omitted and sodium metaborate is added to raise the pH.

Not too many months ago, after being a TF-4 user for decades, I tried a small bottle of TF-5 just to see whether it made any difference in the stain on PMK-developed Delta 100 negatives. None was detectable. Now that my last gallon concentrate of TF-4 is almost gone, even though I don't notice much difference in the odor, I'm considering TF-5 instead. However, an aspect of TF-4's alkalinity I always appreciated is that one can be cavalier about extended fixing times without concern about bleaching. Do you know whether the same applies to TF-5? Thanks in advance.

[Michael R]

Same with TF-5 or any fixer that is close to neutral or higher in pH. The rate of bleaching action of fixer is directly related to acidity, which is why it was something more important to watch out for when more acidic hardening fixers were the norm. Even Ilford Rapid Fixer would be much slower to bleach than older alum hardening formulas. At pH 6.5-6.8 (TF-5) it’s a non issue. If I remember correctly Ron even tested for it just to dot the Is and cross the Ts.


Not too many months ago, after being a TF-4 user for decades, I tried a small bottle of TF-5 just to see whether it made any difference in the stain on PMK-developed Delta 100 negatives. None was detectable.

Now that my last gallon concentrate of TF-4 is almost gone, even though I don't notice much difference in the odor, I'm considering TF-5 instead. However, an aspect of TF-4's alkalinity I always appreciated is that one can be cavalier about extended fixing times without concern about bleaching. Do you know whether the same applies to TF-5? Thanks in advance.

[Tin Can]

I always trusted Ron

[Michael R]

Definitely a good source, and always helpful in my experience. I went to him with lots of rather arcane topics/questions in my years on APUG/Photrio, and he was always gracious. His death was a blow.


I always trusted Ron

[Tin Can]

Just to remind

I count sheets to decide when to replace TF5

as it seems to never lose speed