TF-4 User For Years...Want To Try TF-5

[John Layton]

....but its been difficult for me to suss out the pluses and minuses of each - aside from noting opinions about TF-4 being more odiferous than TF-5.

Another thing...what about working dilution capacity - in terms of square inches of film? The only literature I can find says that one gallon of working solution can fix 20 rolls of film...huh? I've been using TF-4 to way less than its stated capacity just to be on the safe side - and I still can do way more square inches of LF film than a 20 roll equivalent! Perhaps PF is assuming a "one-shot" method?

At any rate...I'd be using TF-5 just as I had TF-4 - to fix LF films souped in either Pyrocat or PMK developers - and if anyone here could comment on their own experiences with TF-5 so utilized, as well as any notable differences compared to TF-4...that would be great!

[Drew Wiley]

I can't answer your question, but would myself be a candidate for the answer. I use TF4 for both film and paper. But so far, I see no reason to switch. Its alkalinity seems to help residual dye stains wash out from the film base much better than conventional fixers. That fact is not either evident or particularly important when a pyro stain is present, and ordinary black and white printing is in mind. But I often make contrast masks for color printing, internegs, etc, from both TMax and FP4, using conventional developers, where any remaining tint (pinkish is these cases) can cause a real problem. I always use TF4 1:3 one-shot. The only advantage I hypothetically see to TF5 is that the jug of concentrated solution might not settle as bad, and not need as much initial agitation. I don't have any problem with the modest odor because I have a good fume hood.

[Michael R]

They will fix the same and wash the same. Neither will have any affect on imagewise stain (nor will any other non-hardening rapid fixer). TF-5 is neutral rather than alkaline so less odour than TF-4. TF-5 doesn’t have the sludge to mix. I would use TF-5 if I were inclined to bother with any TFs.


....but its been difficult for me to suss out the pluses and minuses of each - aside from noting opinions about TF-4 being more odiferous than TF-5.

Another thing...what about working dilution capacity - in terms of square inches of film? The only literature I can find says that one gallon of working solution can fix 20 rolls of film...huh? I've been using TF-4 to way less than its stated capacity just to be on the safe side - and I still can do way more square inches of LF film than a 20 roll equivalent! Perhaps PF is assuming a "one-shot" method?

At any rate...I'd be using TF-5 just as I had TF-4 - to fix LF films souped in either Pyrocat or PMK developers - and if anyone here could comment on their own experiences with TF-5 so utilized, as well as any notable differences compared to TF-4...that would be great!

[Tin Can]

I don't ONE Shot TF5

Must use Distilled

Very economical

I buy a 4 gallon case, as shipping is cheaper

I store in a floating lid tank

It has a spigot, any crap goes to bottom

Looks like Arkay may not have them

[Drew Wiley]

Michael - Please clarify your statement. Don't tell me NEITHER will have an effect on residual image stain (referring to remaining anti-halation DYE rather than pyro stain, if that is in fact what you meant - perhaps not - "imagewise stain" would seem to mean the proportional pyro stain instead). I've been working with TF4 as long as its been around, and it is unquestionably superior at facilitating TOTAL rapid removal during the wash step of any residual ANTIHALATION DYE on TMax films, somewhat less in the case of FP4, but still an improvement. Traditional fixers tend to make those stains even more stubborn.

[Michael R]

I was referring to imagewise stain from pyrogallol or catechol developers, which OP referred to. Regarding anti-halation dyes/TMax and fixers, bogus. But use whatever you want. They all do the job.


Michael - Clarify your point. Don't tell me NEITHER will have an effect on residual image stain (referring to remaining anti-halation DYE rather than pyro stain, if that is in fact what you meant). I've been working with TF4 as long as its been around, and it is unquestionably superior at facilitating TOTAL rapid removal during the wash step of any residual dye on TMax films, somewhat less in the case of FP4, but still an improvement. Traditional fixers tend to make those stains even more stubborn.

[Drew Wiley]

Thanks Michael, that's what I thought you meant. But your added "Bogus" ain't a bonus at all. It's what I'm specifically interested in finding out; and you're clearly not one who has the answer. Here's just one of the reasons: yes, a bit of magenta cast can easily be filtered out when color printing; but that stain fades over time with UV exposure, so will affect color balance differentially with reapplication. For example, TF4 typically has about 4cc M out of the wash. TMax films have essentially zero after TF4 and a 10 min wash (net fbf only around .05 with TMY, and it doesn't change over time). So when those masks get used for not only color printing, but perhaps in relation to critical color separations etc, removing all the remaining dye first is important. Ordinary silver printing of pyro negs is a whole different issue. If that's all was involved, I would even be curious. As the saying goes, If it ain't broke, don't fix it.

[John Layton]

...although I suppose that for those who just use tap water for everything, and who's water supply is acidic - the higher alkalinity of TF-4 may help to ensure that Pyro-based developers can still develop a good image stain. Make sense?

At any rate, while I use distilled water to mix chemicals, I do use three successive trays of tap water as a stop bath - but then again, our tap water is already slightly alkaline...and I'm filtering down to 5 microns.

[Michael R]

...although I suppose that for those who just use tap water for everything, and who's water supply is acidic - the higher alkalinity of TF-4 may help to ensure that Pyro-based developers can still develop a good image stain. Make sense?

The pH of your water is irrelevant. Water has essentially no buffering capacity so its pH is totally overwhelmed by the chemicals you add to it. Furthermore imagewise stain from pyrogallol or catechol developers will not depend on whether or not the fixer is alkaline. You can use virtually any commercially available non-hardening rapid fixer including Ilford (mildly acidic), TF5, Sprint, Flexicolor/C-41 etc. (all neutral), TF4 etc. (alkaline)…

The only caveat with alkaline fixers is it is good practice to do a thorough rinse or stop bath between development and fixation to avoid the possibility of development re-starting in the fixing bath.

[Tin Can]

If I had an ocean

I would try sea water

[Michael R]

Sea water does make a good wash medium (it’s like a weak hypo clearing agent), and can even be a very very very slow fixer mostly for silver chloride emulsions so yeah sea water is pretty neat.


If I had an ocean

I would try sea water

[John Layton]

Michael, I've been making inferences from Gordon Hutchings Book of Pyro...first edition - specifically, the section which begins on page 54 entitled "pH and Stain," which, while I won't retype the entire section here - starts with "Pyro stain is PH sensitive. Alkaline solutions increase stain and acid solutions tend to reduce stain."

Then again...I'd always used a used-developer after bath, which G. Hutchings, in his later edition(s?), stated was unnecessary as it only added to general overall stain (and thus density), while not specifically affecting various actual film densities.

Not sure if the above ties into anything going forward regarding density-specific staining, but as I've not tried PMK for a few years (have been using Pyrocat), I do plan to retry PMK without the after-bath.

At any rate...just a few thoughts - and I appreciate your feedback!

[Drew Wiley]

I got once taken to task on that point, John. And it seems all an alkaline afterbath does for PMK is increase an fbf effect of overall stain, and not differential stain, especially with semi-thick films like HP5 more than thinner emulsion films. I've worked with other pyrogallol and pyrocat tweaks, and developer alkalinity is important for the whole suite of ingredient activity. Here we enjoy high water quality piped in from mountain snowmelt reservoirs, so I only use distilled for the final brief rinse of film. But in much of the West, especially from private wells, the alkalinity of the water can be a significant factor itself. Michael should take a tour someday and sample the taste of real "hard water", with my first recommended stop being Stovepipe Wells in Death Valley. Kinda like a wine tasting tour for darkroom workers, but at times more like a soap tasting experience.

[Michael R]

Yes the Book of Pyro... not a very good book about pyro. :) In any case, the point is TF-5 will work every bit as well as TF-4. That includes negatives processed in staining developers. There is nothing about TF-5 relative to TF-4 which will reduce imagewise stain density, and there is certainly nothing about TF-4 (or any fixer) which would increase imagewise stain formed in development.

Not sure what Drew is on about but I would say it is probably best to avoid using say Mono Lake as a water source for photographic or non photographic purposes.


Michael, I've been making inferences from Gordon Hutchings Book of Pyro...first edition - specifically, the section which begins on page 54 entitled "pH and Stain," which, while I won't retype the entire section here - starts with "Pyro stain is PH sensitive. Alkaline solutions increase stain and acid solutions tend to reduce stain."

Then again...I'd always used a used-developer after bath, which G. Hutchings, in his later edition(s?), stated was unnecessary as it only added to general overall stain (and thus density), while not specifically affecting various actual film densities.

Not sure if the above ties into anything going forward regarding density-specific staining, but as I've not tried PMK for a few years (have been using Pyrocat), I do plan to retry PMK without the after-bath.

At any rate...just a few thoughts - and I appreciate your feedback!

[Mark Sampson]

i've been using TF-5 for film and paper for a while now. It works very well, doesn't stink, and my FP4+ negatives developed in Pyrocat have a definite "imagewise" stain. I also use a citric acid stop bath, and my darkroom no longer smells like... a darkroom.
I'm quite satisfied with PF's product and have no plans to change back to anything else.
Sometimes improvements are indeed possible. Go for it John!

[MAubrey]

I'm a big fan of TF-5.

[Doremus Scudder]

No word yet about TF-5 capacity compared to TF-4 or other rapid fixers.

Really, I'm at a loss understanding why capacities should be different for the TF family of fixers compared with, say, Ilford Rapid Fixer or Hypam. If there's really no difference, then one could use the Ilford tech sheets for these products as a guide for capacity and fixing times. The Ilford literature is detailed and includes capacity numbers for both "general purpose/commercial" and "optimum permanence" levels of fixation. I found the capacity numbers for the TF products to be rather sketchy and incomplete.

Michael R, any comments?

Best,

Doremus

[Drew Wiley]

TF info is straightforward, namely, with capacities intended for one-shot use, not re-use. Since they sell it as an "archival fixer", optimum permanence is the only game in town. It's not sold as a "general purpose" ordinary fixer meant to be used to the point of sheer exhaustion, or requiring a second bath. Bend the rules at your own risk. But they no doubt give somewhat conservative specs to provide a reasonable margin or error with reference to fixing time as well as dilution.

[Michael R]

Hi Doremus, unfortunately the tech sheets for both TF-4 and TF-5 (like many PF products) are mostly marketing/hyperbole so there is not a great deal of information. The instructions for both indicate the following suggested capacities per liter of working solution:

15-20 rolls of film (or sheets of 8x10 or x4 sheets of 4x5)
30 sheets of 8x10 FB paper
60 sheets of 8x10 RC paper

That’s all we really have to go on. Fundamentally they are all principally ammonium thiosulfate likely in very similar working concentrations so when in doubt Ilford’s capacities can safely be relied upon to be conservative. Additional active/synergistic ingredients in the Formulary products which may or may not affect capacities are trade secrets so it is difficult to say much more about them. In the case of TF-5, since Ron (PE) had a hand in it, it is possible it is derived from one of his several rapid access superfix formulas (2-7, not disclosed) but we don’t know. I recall him discussing aspects of TF-5 on APUG so perhaps searching his posts on the subject would shed more light. Ron did not write the instructions on Formulary’s site.

People tend to make way too much of this, based mostly on bad and/or outdated/out of context information. If I were determined to not use Ilford Rapid Fixer and wanted something a little closer to neutral I’d either use Sprint (incidentally has higher indicated working solution capacities than the Formulary products), C-41/Flexicolor, or just mix my own (ammonium thiosulfate with some sulfite/bisulfite, which will have the same capacity as Ilford etc.).

Just one quick note of trivia for the pyro users - John Wimberley, the “father” of “modern” pyro formulas (PMK was based on WD2D) has always used plain old Ilford Rapid Fixer.


No word yet about TF-5 capacity compared to TF-4 or other rapid fixers.

Really, I'm at a loss understanding why capacities should be different for the TF family of fixers compared with, say, Ilford Rapid Fixer or Hypam. If there's really no difference, then one could use the Ilford tech sheets for these products as a guide for capacity and fixing times. The Ilford literature is detailed and includes capacity numbers for both "general purpose/commercial" and "optimum permanence" levels of fixation. I found the capacity numbers for the TF products to be rather sketchy and incomplete.

Michael R, any comments?

Best,

Doremus

[Drew Wiley]

I had a jug of that Ilford Rapid Fix on hand, and no, it did not work as well for my PMK pyro purposes as TF4. Gordon Hutchings got it right, and certainly was the father of the current popularity of pyrog. developers.

[Michael R]

It was Wimberley who started the revival in the late 1970s. Also Hutchings used regular mildly acidic Kodak fixers. In any case it doesn’t matter. If you like TF-4 there is no reason not to use it. As long as there is sufficient rinsing/stopping between development and fixation alkaline fixers are perfectly good. The more alkaline, the stronger the ammonia odour tends to be so buffering to a mildly alkaline pH is preferable. TF-4 is fine.


I had a jug of that Ilford Rapid Fix on hand, and no, it did not work as well for my PMK pyro purposes as TF4. Gordon Hutchings got it right, and certainly was the father of the current popularity of pyrog. developers.

[Roger Cole]

This thread is of interest to me as I'm getting back into photography after a several years hiatus meaning that liquid fixers will need to be discarded and replaced (from what I read in that other thread on the bad batches of Kodak RF, they tend to sulferize over some period after which they are useless.)

I've used crtric acid based stop baths for years as my darkroom was never ventilated very well (if at all, sometimes.) My new darkroom (building out the rest of my basement, including plumbing, lead me to think "hey I could finally have a PROPER darkroom..." and that lead to getting excited about getting back into photography and here I am) will be better ventilated, but if there's no downside to something like TF-5 then I might as well use it.

If The Book of Pyro isn't a great book about pyro, what is? I've never used it, read enough about it years ago to be familiar with the general idea back then but never tried it. If I wanted to try it out, where would be the place to read about it? A bit of aside thread-creep, I know, but TF-5 sounds like a winner with no real downside.

[Tin Can]

I use food grade citric acid powder for paper stop

TF5 was designed by 'PE' Photo Engineer RIP

I think he worked for KODAK

There are many references and examples only on APUG where is was authoritative

He sold me

and John

just do it



This thread is of interest to me as I'm getting back into photography after a several years hiatus meaning that liquid fixers will need to be discarded and replaced (from what I read in that other thread on the bad batches of Kodak RF, they tend to sulferize over some period after which they are useless.)

I've used crtric acid based stop baths for years as my darkroom was never ventilated very well (if at all, sometimes.) My new darkroom (building out the rest of my basement, including plumbing, lead me to think "hey I could finally have a PROPER darkroom..." and that lead to getting excited about getting back into photography and here I am) will be better ventilated, but if there's no downside to something like TF-5 then I might as well use it.

If The Book of Pyro isn't a great book about pyro, what is? I've never used it, read enough about it years ago to be familiar with the general idea back then but never tried it. If I wanted to try it out, where would be the place to read about it? A bit of aside thread-creep, I know, but TF-5 sounds like a winner with no real downside.

[Doremus Scudder]

I had a jug of that Ilford Rapid Fix on hand, and no, it did not work as well for my PMK pyro purposes as TF4. Gordon Hutchings got it right, and certainly was the father of the current popularity of pyrog. developers.

Strange, I've compared PMK negatives with both TF-4 and Ilford Rapid Fixer and found absolutely zero difference; stain was the same, base fog was the same (visual comparison only, but that should be adequate in this case).

The thing that gets me about simply saying that capacity is "30 8x10s per liter" for TF-4/TF-5 is the discrepancy with the Ilford information. Ilford states that for "optimum permanence," the capacity of their Rapid Fixer is only 10 8x10-inch prints per liter (assuming single bath use) while for "commercial" standards, the capacity increases to 40 8x10s per liter. Here's the relevant section from the Ilford tech sheet:

"If a high level of image permanence is required for commercial use the silver concentration in the fixer should be kept below 2 g/l when fixing FB
papers. This approximates to 40, 20.3 x 25.4 cm, (8 x 10 inch) FB prints. Above this level compounds may remain in the paper base after washing and over time possibly contribute to print staining. For prints that need maximum stability for long term storage a the maximum silver level in the fixer should not rise above 0.5 g/l i.e., approximately 10 20.3 x 25.4cm (8 x 10in) prints." [emphasis added]

If, as it seems logical to extrapolate from the Ilford information, the capacity of the fixer is linked directly to the amount of dissolved silver in the fixing bath, then why in the world should the TF fixers be any different? Is there some "secret ingredient" that allows more thorough fixing at a higher concentration of dissolved silver? And, if so, why aren't the manufacturers/distributors shouting this from the rooftops, since it would make great marketing?

I'm sure Ron Mowrey did his research and has/had all kinds of data about dissolved silver concentrations vs. efficiency and completeness of fixing, but I've certainly never seen any of them. At least Ilford gives you some reasoning for why they recommend certain capacities.

And, if as Michael suggests, the TF products are similar in activity and capacity to Ilford and other rapid fixers, why is the capacity for those fixers listed as some number between Ilford's "commercial" and "optimum permanence" standards?

It's not that I couldn't test myself for adequate fixation using ST-1 or the KRST tests (however imprecise and unquantifiable those are); I do those tests regularly when printing. It's just that I would expect that a product that was so carefully developed for a specific and discriminating market to have much, much better documentation.

I quit using TF-4 for other reasons, but until I really am convinced that TF-5 or whatever is substantially better than the Ilford products I'm currently using, I'll stick with them. PF could go a long way toward convincing me that their products were as good or better if they'd simply publish the research data in more detail.

Best,

Doremus

[Bernice Loui]

From previous LFF discussion about pyro developers, note post# 23 by Steve Simmons regarding W2D2 and PMK.
https://www.largeformatphotography.info/forum/showthread.php?18006-Pyrocat-HD-in-Glycol-Step-bt-Step-Mixing-Instructions/page3

"Now, suddenly, a new group has rediscovered the wheel, or perhaps they think they have invented the wheel, with new staining developers. It is touted as being the best, etc., etc. In reality it/they are just a variation of an older wheel. If you like it fine. Use whatever you like. But it is not revolutionary by any means. Wimberly and Hutchings did something that could be called evolutionary. The fact that not everyone thinks these brand new formula are better wheels should not result in them being personally attacked."

BTW, John Wimberly had 16x20 prints on display at Keeble & Shuchat in Palo Alto CA.. John Wimberly was among a long list of others that displayed prints at Keeble & Shuchat back in them days..


Bernice




If The Book of Pyro isn't a great book about pyro, what is? I've never used it, read enough about it years ago to be familiar with the general idea back then but never tried it. If I wanted to try it out, where would be the place to read about it? A bit of aside thread-creep, I know, but TF-5 sounds like a winner with no real downside.

[Roger Cole]

From previous LFF discussion about pyro developers, note post# 23 by Steve Simmons regarding W2D2 and PMK.
https://www.largeformatphotography.info/forum/showthread.php?18006-Pyrocat-HD-in-Glycol-Step-bt-Step-Mixing-Instructions/page3

"Now, suddenly, a new group has rediscovered the wheel, or perhaps they think they have invented the wheel, with new staining developers. It is touted as being the best, etc., etc. In reality it/they are just a variation of an older wheel. If you like it fine. Use whatever you like. But it is not revolutionary by any means. Wimberly and Hutchings did something that could be called evolutionary. The fact that not everyone thinks these brand new formula are better wheels should not result in them being personally attacked."

BTW, John Wimberly had 16x20 prints on display at Keeble & Shuchat in Palo Alto CA.. John Wimberly was among a long list of others that displayed prints at Keeble & Shuchat back in them days..


Bernice

Thanks Bernice. That was pretty much my conclusion when i read up on them way back when - interesting, but didn't seem to offer that much advantage, if any. But if I'm restarting my photography after several years, which is what I plan to do, it's not a bad time to revisit such questions.

[Bernice Loui]

Used PMK back when (circa later 1990's) it was introduced by Gordon H, which prompted trying other Pyro developers like W2D2...

As mentioned by Steve S, they are not a lot more than another "tool" in the tool box to achieve an image goal results.
There are no "magic elixirs" just what might be the better solution to a given need and problem to be solved.. Awful lot of this has to do with fully understating what this stuff does and cannot do, then apply as needed.


Bernice




Thanks Bernice. That was pretty much my conclusion when i read up on them way back when - interesting, but didn't seem to offer that much advantage, if any. But if I'm restarting my photography after several years, which is what I plan to do, it's not a bad time to revisit such questions.

[Michael R]

Doremus, just some things to keep in mind which make direct comparisons difficult:

1. Different assumptions regarding acceptable final amounts of retained thiosulfate/silver-thiosulfate complexes in the paper for different levels of permanence.

2. Initial concentration of thiosulfate per litre of working solution, although similar, may not be the same

3. The allowable concentration of silver depends to some extent on fixing time assumptions. For example, Kodak suggests a capacity for its rapid fixer of ~25 8x10s/litre working solution at half the concentration of the dilution for film fixation (so more prints than Ilford, and at a lower concentration than Ilford) but with much longer fixing time.

4. Capacities based on the silver content of the fixing bath are basically assuming these are insoluble complexes. However there are compounds which can be added to a thiosulfate fixer which can increase the solubility of fixing by-products. There was research into this at Kodak etc. mostly in the context of rapid access processing. Some of the more obvious ones have potential downsides such as gelatin softening but Ron hinted at others. TF5 and TF4 do contain additional ingredients not present in standard rapid fixers, and these may (or may not) affect throughput capacity.

5. Besides Ilford’s thoroughly disclosed research into fixing times and washing with respect to permanence, manufacturers’ instructions are basically “black boxes”. Rely on them or don’t. We know companies like Kodak did the work, so taking their recommendations at face value is sensible. Other companies? Not as clear. There’s probably some extrapolation going on, but that isn’t necessarily unreasonable. After all, fixation of photographic materials is quite well understood and has been around for a very long time.

I would say whenever venturing into non-Ilford/non-Kodak fixers, some testing (including wash results) is probably wise. Simple stuff like retained silver etc. Or, simply apply Ilford’s instructions. They are the most conservative, so things are unlikely to go wrong.




Strange, I've compared PMK negatives with both TF-4 and Ilford Rapid Fixer and found absolutely zero difference; stain was the same, base fog was the same (visual comparison only, but that should be adequate in this case).

The thing that gets me about simply saying that capacity is "30 8x10s per liter" for TF-4/TF-5 is the discrepancy with the Ilford information. Ilford states that for "optimum permanence," the capacity of their Rapid Fixer is only 10 8x10-inch prints per liter (assuming single bath use) while for "commercial" standards, the capacity increases to 40 8x10s per liter. Here's the relevant section from the Ilford tech sheet:

"If a high level of image permanence is required for commercial use the silver concentration in the fixer should be kept below 2 g/l when fixing FB
papers. This approximates to 40, 20.3 x 25.4 cm, (8 x 10 inch) FB prints. Above this level compounds may remain in the paper base after washing and over time possibly contribute to print staining. For prints that need maximum stability for long term storage a the maximum silver level in the fixer should not rise above 0.5 g/l i.e., approximately 10 20.3 x 25.4cm (8 x 10in) prints." [emphasis added]

If, as it seems logical to extrapolate from the Ilford information, the capacity of the fixer is linked directly to the amount of dissolved silver in the fixing bath, then why in the world should the TF fixers be any different? Is there some "secret ingredient" that allows more thorough fixing at a higher concentration of dissolved silver? And, if so, why aren't the manufacturers/distributors shouting this from the rooftops, since it would make great marketing?

I'm sure Ron Mowrey did his research and has/had all kinds of data about dissolved silver concentrations vs. efficiency and completeness of fixing, but I've certainly never seen any of them. At least Ilford gives you some reasoning for why they recommend certain capacities.

And, if as Michael suggests, the TF products are similar in activity and capacity to Ilford and other rapid fixers, why is the capacity for those fixers listed as some number between Ilford's "commercial" and "optimum permanence" standards?

It's not that I couldn't test myself for adequate fixation using ST-1 or the KRST tests (however imprecise and unquantifiable those are); I do those tests regularly when printing. It's just that I would expect that a product that was so carefully developed for a specific and discriminating market to have much, much better documentation.

I quit using TF-4 for other reasons, but until I really am convinced that TF-5 or whatever is substantially better than the Ilford products I'm currently using, I'll stick with them. PF could go a long way toward convincing me that their products were as good or better if they'd simply publish the research data in more detail.

Best,

Doremus

[esearing]

The only difference I have found between TF4 and TF5 was the final color tone given to Moersch's Lobotype print process . It uses an iron and silver coating similar to Kallitype. I have used both with FP4+ and variations of Pyrocat and found it to have no difference other than TF4 always seemed to have more silver/sulfide left in the bottom of the container. TF5 lasts a long time if not frequently used. Undiluted I have made it to 3 years even in partially filled gallon container, diluted at least six months, but I discard if that old or once a test strip takes longer than 30 seconds to clear.
I tend to use TF5 1-9 instead of 1-4 because I do not process much or frequently.

[Tin Can]

PE aka

Ron Mowery worked for KODAK designing TF5

"PHOTOGRAPHIC EMULSION MAKING, COATING AND TESTING" BOOK BY RON MOWREY

Available at https://stores.photoformulary.com/photographic-emulsion-making-coating-and-testing-book-by-ron-mowrey/

[Doremus Scudder]

Doremus, just some things to keep in mind which make direct comparisons difficult:

1. Different assumptions regarding acceptable final amounts of retained thiosulfate/silver-thiosulfate complexes in the paper for different levels of permanence.

2. Initial concentration of thiosulfate per litre of working solution, although similar, may not be the same

3. The allowable concentration of silver depends to some extent on fixing time assumptions. For example, Kodak suggests a capacity for its rapid fixer of ~25 8x10s/litre working solution at half the concentration of the dilution for film fixation (so more prints than Ilford, and at a lower concentration than Ilford) but with much longer fixing time.

4. Capacities based on the silver content of the fixing bath are basically assuming these are insoluble complexes. However there are compounds which can be added to a thiosulfate fixer which can increase the solubility of fixing by-products. There was research into this at Kodak etc. mostly in the context of rapid access processing. Some of the more obvious ones have potential downsides such as gelatin softening but Ron hinted at others. TF5 and TF4 do contain additional ingredients not present in standard rapid fixers, and these may (or may not) affect throughput capacity.

5. Besides Ilford’s thoroughly disclosed research into fixing times and washing with respect to permanence, manufacturers’ instructions are basically “black boxes”. Rely on them or don’t. We know companies like Kodak did the work, so taking their recommendations at face value is sensible. Other companies? Not as clear. There’s probably some extrapolation going on, but that isn’t necessarily unreasonable. After all, fixation of photographic materials is quite well understood and has been around for a very long time.

I would say whenever venturing into non-Ilford/non-Kodak fixers, some testing (including wash results) is probably wise. Simple stuff like retained silver etc. Or, simply apply Ilford’s instructions. They are the most conservative, so things are unlikely to go wrong.

Thanks Michael,

Yeah, I'm aware of all the parameters you mention. It's just that I don't know enough about fixer formulation and the complex chain of reactions that end up producing the soluble argentothiosulfate compounds to be able to assess capacity claims for various fixers from different manufacturers. That's why I've always used Kodak/Ilford products, assuming that their research is thorough and sound. When capacity claims for other, ostensibly similar, fixers don't jibe with the capacity claims from Kodak and Ilford, and when there's no reference to any research backing up those claims, I get a bit skeptical.

For example, the TF-5 instruction sheet makes no reference to what standard of fixation is being targeted (vs Ilford's "commercial" and "optimum permanence" standards). One could assume that such a product was designed for "archival" processing, but if so, then why is the capacity listed three times that of the Ilford fixers? If a product really is superior, one would think that the manufacturer would want to demonstrate that to the potential customers. Not doing so makes me think that there's nothing behind the claims.

If/when I get around to switching to TF-5 or whatever, I'll just have to do my own throughput capacity tests using ST-1 or the KRST tests. I've done this for the Ilford products, so, unless I suddenly feel like testing out a new fixer just for the fun of it, I likely won't be changing from Ilford anytime soon.

Best,

Doremus

[Michael R]

Makes sense to me. Like I said, Ron didn’t write the stuff on the PF site for TF-5.


Thanks Michael,

Yeah, I'm aware of all the parameters you mention. It's just that I don't know enough about fixer formulation and the complex chain of reactions that end up producing the soluble argentothiosulfate compounds to be able to assess capacity claims for various fixers from different manufacturers. That's why I've always used Kodak/Ilford products, assuming that their research is thorough and sound. When capacity claims for other, ostensibly similar, fixers don't jibe with the capacity claims from Kodak and Ilford, and when there's no reference to any research backing up those claims, I get a bit skeptical.

For example, the TF-5 instruction sheet makes no reference to what standard of fixation is being targeted (vs Ilford's "commercial" and "optimum permanence" standards). One could assume that such a product was designed for "archival" processing, but if so, then why is the capacity listed three times that of the Ilford fixers? If a product really is superior, one would think that the manufacturer would want to demonstrate that to the potential customers. Not doing so makes me think that there's nothing behind the claims.

If/when I get around to switching to TF-5 or whatever, I'll just have to do my own throughput capacity tests using ST-1 or the KRST tests. I've done this for the Ilford products, so, unless I suddenly feel like testing out a new fixer just for the fun of it, I likely won't be changing from Ilford anytime soon.

Best,

Doremus