Hello, a few questions about TF4 alkaline fixer and stop bath

[Ales']

What is worst case scenario if I just put my film from developer in to plain hypo or tf4 tray? In case you wonder why, my sink can hold only 3 8x10 trays or 2 11x14 and I want to move to 24x30cm size

 

[Neal]

What is worst case scenario if I just put my film from developer in to plain hypo or tf4 tray? In case you wonder why, my sink can hold only 3 8x10 trays or 2 11x14 and I want to move to 24x30cm size

You should have no problems.

 

[Scott J.]

Does anyone know what the undissolved sediment in the concentrate is?

I recall Ron Mowrey stating several years ago that one could create a close approximation of TF-4 by simply following the published recipe for TF-3. The active solutes in TF-3 are (in decreasing order of concentration): ammonium thiosulfate, sodium sulfite, and sodium metaborate. Of the three, ammonium thiosulfate is the most soluble in water (173 g/100 mL @ 20 deg. C), while sodium sulfite and sodium metaborate are considerably less soluble (both around 27 g/100 mL @ 20 deg. C, which it should be noted is still quite soluble).

According to the SDS for TF-4, ammonium thiosulfate (the only ingredient required by law to be listed) is present at a concentration of 10-15%. The SDS is a little vague on what it means by "%," as this can be interpreted a couple different ways, but most likely what the authors meant was "weight percent" -- i.e., weight of solute divided by total weight of solution. The density of the TF-4 concentrate is reported as 1.07 g/cm3, so if we assume an ammonium thiosulfate concentration of 15 weight percent, that means one liter of concentrate has a total mass of 1,070 g, and therefore contains 160.5 g of ammonium thiosulfate. This is well below the solubility threshold for ammonium thiosulfate, so it's probably safe to assume it's all in solution.

My guess, then, is that the white precipitate in the concentrate is some mixture of sodium sulfite and/or sodium metaborate. It may be that the relatively higher concentration of the ammonium thiosulfate in the concentrate is preventing these other components from dissolving. This also likely explains why TF-4 is touted as an "alkaline fix" despite the concentrate having an SDS-reported pH of 5. In aqueous solution, ammonium thiosulfate has a pH of 6-7, while sodium sulfite and sodium metaborate have pHs of approximately 8 and 10, respectively. When the concentrate is diluted to the working solution (1+3), the ammonium thiosulfate concentration is decreased, which then presumably allows the sodium sulfite and sodium metaborate to go into solution, which in turn clarifies the solution and increases the pH.

I'm guessing the concentrate has an acidic component, too, that helps with stability, which may explain why it has a pH of 5. The presence of this acidic component may also be interfering with the solubility of the sodium sulfite and sodium metaborate, such that only after it has been diluted below some threshold can the alkaline components fully dissolve.

 

[Richard Jepsen]

Last year I got troublesome spots on my negs that would not wash off with a 15 min rewash. I determined it was some form of TF-4 solid. I’ve used TF-4 since 2005 with no issues. I assume I was at fault for not mixing it enough. Since than I switched to TF-5 which avoids the settled goop. I read on a PE post that when using a paper developer with one of the active ingredients ( I can’t recall which one) an acidic stop bath was helpful. So I am splitting hairs and now use a very weak (1/3 recommended) citrus stop bath while printing. I typically process 20 8x10 RC prints and toss the fix or use a two fix process with FB with lower through put. During a DR session I print about 4 or 5 8x10s. I don’t experience any issues and I have no odors in my non vented laundry room.

 

[Richard Jepsen]

I had my first experience with TF5 fixer today, in conjunction with FP4 sheet film and PMK developer. It worked just like TF4, except that I got emulsion edge frilling - something I have never seen before with FP4 in my life. It was only at the very margins of the sheets, and not into the image area at all, so these are still perfectly printable. But it sure took me by surprise. Next time I'll try an extremely weak acetic acid stop bath, like I once used for Efke film, and see what happens.

Do you think TF-5 fixer can promote print frilling with Ilford FB? I have been having this issue. I used to use TF-4 but moved away from it for film fixing as I experienced unwanted deposits likely from not being well mixed.

 

[bluechromis]

The general idea with an alkaline fixer is to keep the whole process alkaline. There is no real reason to use an alkaline fixer with an acid stop bath. If you want to use a n acid stop bath rather than a water bath (a point not worth debating again) then just use regular acidic or neutral fixer. They are easier and cheaper to get.

The data sheet for TF-4 says:

It could be argued there is little reason to use an acid fixer in the modern era. It has been known all along that alkaline/neutral fixers offer better performance such as faster fixing and greater capacity. The historic reason acid fixers are prevalent is that old emulsions required a hardening fix and acid is what worked with hardeners. But those soft emulsion films are long gone, and with them, the imperative to use acid fixers.

An acid stop is not required with an alkaline fixer, but if one really wants to do that they can. TF-4 is buffered to deal with acid stops. Even if one uses an acid stop, alkaline fixers are still advantageous because of their improved performance and because one does not need a clear (HPA) bath, eliminating one step from the process.

 

[bluechromis]

Ron Mowrey/PE who was one of the formulators of TF-4 recommended using an acid stop bath with alkaline fixers, he had seen dichroic fogging a few times with just a water stop bath.



Is TF-4 an Alkaline fixer, the concentrate has a pH of 5 according to the MSDS, the working solution closer to pH6, that's the wrong side of pH 7 - Neutral to be Alkaline. My understanding from what Ron wrote was TF-4 was buffered to be close to neutral when mixed with water and remain odourless, and that without an acid stop bath it could become alkaline and cause Dichroic fog and also Ammonia fumes

Ian

Bill Troop was the other co-formulator of TF-4 and TF-5. He advocates using a water bath. He said that getting dichroic fog was unlikely with modern emulsions. Do we know when in the P.E.'s very long career he experienced the fog? Was it just with old emulsions? Is d. fog from fixer just a legend today? Is anybody really having issues with that?

As I understand it, the conditions where someone could possibly get d. fog is with a very strong developer and a weak fixer. If our fixer is approaching exhaustion, it raises all kinds of risks, not just fog. So it is better to maintain a fresh fixer and avoid the problems altogether.

 

[bluechromis]

??? Please explain why not when every film/chemical manufacturer states to use a stop bath between developer and fix?

Good grief, hasn't the discussion between vinegar and stop been beaten to death?

How long does the fixer last if constantly exposed to developer last?

I know that you're a chemist, but??? I'm at a loss.

Sirius Glass should chime in here.

If we are citing manufactuers' film tech sheets as the source of advice about stop baths, there may be reasons to question that. It is possible to go overboard in viewing tech sheets as sacred texts to be followed to the letter.

Although neither Ilford nor Kodak says it, there are people who claim one should only use developers listed in the tech sheet for the film because the manufacturers are saying that using any other developer would be problematic. There are even people who say one should only use the dilutions, film speeds, dev. times, agitation style listed in the tech sheet.

We have to understand that the purpose of the tech sheets is to provide basic instructions to fit the situation of the way people would most commonly use the film. They are not meant to cover all situations They wouldn't have space, for example, to list all the permutations of how films could be successfully exposed or developed. That does not mean those other ways cannot work.

Manufacturers also say that the development times in the tech sheets are starting points but that users should do their own tests. So they are opening the door to a more liberal interpretation of tech sheet instructions for knowledgable users based on individual needs. If this is true of exposure and development times, why would it not also be true of other aspects of chemistry such as fixer?

Most people still use acid fixers so it is a safe thing in the tech sheet to recommend an acid stop. Manufacturers also sell stop baths. Is there any doubt that the lists of developers in the tech sheets are not somewhat self-promotional?

Ilford says a water rinse can be used but says it can deplete the fixer more rapidly. This may be more of a problem if one is carrying over traces of alkaline developer into an acid fixer. If one used neither a water bath nor an acid stop, that would be hard on the fixer. But is there really a big difference in the longevity of the fixer between an acid stop and an adequate water bath?

Also, there is the time warp. Kodak stopped all R&D on BW chemistry in the nineties and then stopped manufacturing chems themselves. Alaris and Eastman now have few personnel knowledgeable about BW chemistry. Ilford isn't much better. There's no innovation there. They are detached from current developments in chemistry, coasting on inertia. So it would not be surprising that their tech sheets would reflect that.

 

[RalphLambrecht]

??? Please explain why not when every film/chemical manufacturer states to use a stop bath between developer and fix?

Good grief, hasn't the discussion between vinegar and stop been beaten to death?

How long does the fixer last if constantly exposed to developer last?

I know that you're a chemist, but??? I'm at a loss.

Sirius Glass should chime in here.

to not contaminate the fixer with the developer. But the whole idea of an alkaline fix is to keep acid out of the process. Stop with water if using an alkaline fix,or better yet, use a two-fix process.

 

[bluechromis]

If, for whatever reason, you want to stay alkaline throughout the process, then a stop bath made from 100 g/l KBr + 20 g/l NaHCO3 has near infinite shelf life and can be set at any pH you want, e.g. near neutral slightly alkaline with Sodium Bicarbonate alone, slightly more alkaline by adding Sodium Carbonate.

This could be a useful development. Anchell and Troop in FDC that alkaline stop baths were still experimental. But perhaps they have matured now.

 

[bluechromis]

TF-2 is not a rapid fixer and therefore quite inferior to TF-3/4/5. TF-3 was the last one of Bill's fixers with a public formula.



I would expect TF-3 and TF-4 to reek to high heaven in an open tray, but TF-5 should be completely odorless at pH 6.5.

My mistake, I meant to say TF-3. You are correct that TF-2 is not a rapid fixer.

 

[Rudeofus]

This could be a useful development. Anchell and Troop in FDC that alkaline stop baths were still experimental. But perhaps they have matured now.

I am afraid, that maturity of these stop bathes didn't really change much between Anchell&Troop and now. I am not aware of anyone using an alkaline stop bath. I vaguely remember seeing a packaged product once, but can't seem to find it now.

 

[relistan]

It could be argued there is little reason to use an acid fixer in the modern era.

The main reason is they are readily available off the shelf without having to order anything from overseas. If you are making your own then sure, neutral or alkaline is great. I’ve made and used @Rudeofus ’s neutral fixer quite a bit. But Ilford rapid fixer is available a couple of places in town.

 

[DREW WILEY]

TF-4 has a mild ammonia smell in a tray. TF-5 still has a bit of odor, but not much. I always work with good ventilation anyway. I
ALWAYS use a mild acetic acid stop bath with either. I like a distinct "Stop Sign" or red light, not an orange one. I've often gotten mediocre results using plain water in lieu of a real stop bath.

Richard - Edge frilling on FP4 with TF5? - yep, I got some of that on quite OLD sheets of FP4, but not on anything else yet. All the images per se came out fine.

 

[bluechromis]

The main reason is they are readily available off the shelf without having to order anything from overseas. If you are making your own then sure, neutral or alkaline is great. I’ve made and used @Rudeofus ’s neutral fixer quite a bit. But Ilford rapid fixer is available a couple of places in town.

It's a circular thing. Alkaline fixers would be more available if more people bought them. Conversely, manufacturers can get away with selling acid fixers because people keep buying them.

 

[Rudeofus]

It's a circular thing. Alkaline fixers would be more available if more people bought them. Conversely, manufacturers can get away with selling acid fixers because people keep buying them.

Acidic fixers make more sense to vendors: they don't last very long, so "that bottle from yesteryear" has sulfured out and won't be used by anyone else, which would be perfectly possible with neutral fixer. Acidic fixer also offers one less path to image defects, since someone going from alkaline and concentrated developer directly into used fixer will less likely see staining.

About 4 years ago I bought 2 large canisters of "C-41 fixer replenisher concentrate" for less than 100€. These have been fixing everything and anything in our dark room since then, and one canister is still mostly full. Fixer makers hate this trick ...

 

[DREW WILEY]

Alkaline fixers like TF4 and semi-alkaline TF5 seem to be selling quite well here, either direct or by means of major internet suppliers. But the typical neighborhood camera store of sells few darkroom supplies anymore today, and when they do, it's only entry-level student supplies.

And there's nothing wrong with giving a supplementary intermediate plain water rinse between the acidic stop bath step and the fixing step. I often do that.

 

[john_s]

Acidic fixers make more sense to vendors: they don't last very long, so "that bottle from yesteryear" has sulfured out and won't be used by anyone else, which would be perfectly possible with neutral fixer. Acidic fixer also offers one less path to image defects, since someone going from alkaline and concentrated developer directly into used fixer will less likely see staining.

About 4 years ago I bought 2 large canisters of "C-41 fixer replenisher concentrate" for less than 100€. These have been fixing everything and anything in our dark room since then, and one canister is still mostly full. Fixer makers hate this trick ...

I still have Agfa FX_Universal (primarily C-41 fixer, pH around neutral), labelled as from their Melbourne factory, which is still perfectly fine. No trace of sulphur. How long ago was Agfa's demise? I can't remember.