Acidity of fixers

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Steven Lee

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Ready for a meaningless lunch time water cooler discussion? :smile:

A while ago I discovered TF-4 and TF-5 fixers. Their description wants you to believe that they're superior to acidic fixers. Supposedly they're faster acting, don't cause image bleaching, require shorter wash time, a stop bath and hypo clearing are not required. What's not to like?

If all of that is true, why aren't all fixers are near-alkaline then? Surely Ilford isn't stupid by continuing to manufacture and sell their slightly acidic rapid fixer. I have not noticed any difference after switching, but continue to buy TF-5 simply out of habit.

Thoughts?
 

pentaxuser

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It sounds as if alkaline fixers may also may the blind see, the lame walk etc but maybe not 😄

Isn't there an argument that alkaline fixer helps maintain the stain in tanned negatives and I am convinced that there are other reasons which other posters will give but which I forget

Others say that Ilford Rapid Fixer is close enough to neutral to not affect the staining on negatives

If you are not using a staining developer but are using only RC paper then I don't think that there is any reason to use an alkaline developer and Ilford can sleep easily in its bed


Hopefully my last 2 sentences although not deliberately designed to do so, will incense others to set me straight and thereby add to the water cooler discussion

pentaxuser
 

bluechromis

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Anchell and Troop in "The Film Developing Cookbook" cite six advantages for alkaline fixers for film:

1. They allow shorter washing times
2. They do not dissolve image bearing silver so there is less danger of over-fixing
3.Keeping the whole developing system alkaline or neutral improves film permanence "because thiosulfate does not mordant to the image or base." (I looked up mordant at point but I can't remember what it means.)
4. Alkaline fixers have a greater capacity than acid fixers
5. They are easier to formulate and more stable than because thiosulfate is more stable in an alkaline solution.
6. Alkaline fixers can be formulated to have very low odor. (But they don't always have low odor. TF-3 does have a moderate ammonia odor.)
 
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bluechromis

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My understanding it that it has been known since the early days that alkaline fixers had bit of an advantage in performance over acid fixers. So why do acid fixers predominate? It was because in old days the soft emulsions needed hardener and the hardener worked better in acid. But the soft films and need for hardener have been gone for decades. So the main pretext for using acid fixers is gone.

Some like to use an acid stop and worry that the acid stop will degrade an alkaline fixer. My understanding is that the TF series fixers are adequately buffered such there is no problem with an acid stop. Or one could do a rinse after the stop.

There are reports of concerns that if an alkaline fixer is depleted that it could result in dichrotic fog on neg. I have seen Bill Troop say this is not likely to be problem with modern films and typical developers. Plus it bad to use stale fixer for many reasons, best avoid that scenario.
 

bluechromis

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It is likely that the advantages of alkaline fixers over acid are modest. There could be other considerations that are more important. If it is easier or cheaper to get acid, or if one is accustomed to using acid and doesn't want to change, there may not be a compelling reason to use alkaline.
 

bluechromis

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As to why Kodak and Ilford don't offer alkaline fixers if their performance is better? With regard to BW chemistry, Kodak and Ilford are coasting with their products. There has been no innovation from them with fixers in decades and really not much with any BW chemistry. Kodak shut down all it's BW chemistry R & D in the ninities. They haven't made their own chemistry in years. They likely lack the personnel capable of improving chemistry. When they recently revamped the formula for HC-110, I assume that was farmed out to another party, maybe Tetenal. Ilford is not much better. In either case, while their fixers may be pretty good, they represent old, really old, technology.

i could see from Kodak and Ilford's point of view that it would not seem lucrative to invest in bringing out new BW chemistry. Besides, consumers seem pretty happy with their existing products, so why bother? Whatever innovation is happening with chemistry comes from small firms and amateurs.

There may be a circularity in this. Why do consumers buy so much acid fixer? It is partly because that is what Kodak and Ilford offer and it is often assumed their products are best even though in this case they are not. Why do Kodak and Ilford keep offering acid fixers? It's because consumers keep buying them.

TF-6 from Photographers Formulary, on the other hand, was recently formulated by Bill Troop and the Photo Engineer. I think they knew what the were doing and that TF-6 represents the state of the art with fixers. The other TF-fixers are also solid. But Formulary products may not be available in all locales and there are other options as well. Moersch lists an alkaline fixer. There are recipes for home mixing including some in the Photrio resource area.
 
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MattKing

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Most of the more recent Kodak work on fixers has been done on colour film fixers. Kodak C-41 (colour film) fixer is modern, neutral with respect to acidity, relatively inexpensive to make and purchase, long lasting and an excellent fixer for black and white film and papers, provided that there is no need to add hardener.
It has never been marketed for black and white usage to small volume users. It has always been marketed to commercial labs.
 

john_s

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....
It has never been marketed for black and white usage to small volume users. It has always been marketed to commercial labs.
Agfa in Australia labelled FX-Universal Fixer for colour and black and white processes. Its pH was around 7. I have some unopened that has not thrown a deposit from decomposition. It must be 15 years old by now.
 

grain elevator

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The way I see it, acidic fixer has a little advantage in that when used for paper or sheet film in trays, one doesn't have to be religious about the stop bath and can still turn the light on when fixing as the fixer will complete the stopping action.
 

Paul Howell

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I use both, T5 for film and Kodak or a clone for paper, reason for using Kodak Acid for paper is that it better matches my work flow, for me 2 minutes for RC works better than 30 seconds. For most I don't think that is a issue. But for FB, I was told by the Kodak rep in the 70s that a standard fixer washed out of FB more quickly than a rapid, and too be very exacting about time, leaving a FB print in Rapid longer than recommended would make it harder to get all the residual fix washed out. That was in the 70s, in the 60s Kodak was still recommending hypo eliminator for paper.
 

bluechromis

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Most of the more recent Kodak work on fixers has been done on colour film fixers. Kodak C-41 (colour film) fixer is modern, neutral with respect to acidity, relatively inexpensive to make and purchase, long lasting and an excellent fixer for black and white film and papers, provided that there is no need to add hardener.
It has never been marketed for black and white usage to small volume users. It has always been marketed to commercial labs.

Thanks Matt. Are there recipes for these color fixers in a publicly accessible place?
 
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@MattKing using C41 fixer for B&W is a great idea. What times do you use? The official C-41 time is 6:30 at 75-100F, what would this translate to for B&W films at 68F?
 

koraks

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What times do you use?

Dunno about Matt, but I use C41 fixer pretty much all the time. Fuji RA C41 fix in my case (I'd have to look up the exact product number), but 1+6-ish will clear Fomapan 100 in under a minute.
 

MattKing

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@MattKing using C41 fixer for B&W is a great idea. What times do you use? The official C-41 time is 6:30 at 75-100F, what would this translate to for B&W films at 68F?

I don't remember the (quite short) times because it has been a while since I used it, because it isn't as easily obtained by me as the black and white fixers, and most of my prints are on RC, where there is no real advantage either way.
Most of the people that used to use it that I was familiar with were operating group darkrooms.
 

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There are different fixer formulas for "C-41 fixer", and they are formulated quite differently. If you look at standard C-41 fixer, it looks like a somewhat dilute neutral rapid fixer, to be replenished frequently. If you look at C-41 RA process, its fixer is an ultra rapid fixer with high thiocyanate content. Thiocyanate can soften emulsions, so be careful if you process very old or hand coated emulsions with such a fixer.

@bluechromis agree with all you say, except for your statements about "TF-6". TF-5 is Ron's and Bill's latest and greatest.
 

John Wiegerink

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There are different fixer formulas for "C-41 fixer", and they are formulated quite differently. If you look at standard C-41 fixer, it looks like a somewhat dilute neutral rapid fixer, to be replenished frequently. If you look at C-41 RA process, its fixer is an ultra rapid fixer with high thiocyanate content. Thiocyanate can soften emulsions, so be careful if you process very old or hand coated emulsions with such a fixer.

@bluechromis agree with all you say, except for your statements about "TF-6". TF-5 is Ron's and Bill's latest and greatest.

I was wondering about the TF-6 statement too! I thought to myself, "Where have I been not to hear about this". I make my own TF-2 and was wondering if it would be just as cost-effective to buy C-41 fixer instead. I don't mind making TF-2, but I always mind spending more than I have to for the same results. Not a big deal, but us old folks on fixed incomes............Well, you get the drift.
 

Rudeofus

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@Rudeofus this one. I was thinking fixing for 5 minutes for B&W. Thoughts?

The MSDS gives the rough composition of this fixer concentrate. Its working solution looks extremely similar to Ryuji Suzuki's Neutral Rapid Fixer formula. 5 minutes fixer time won't hurt, but is probably longer than necessary. The ideal fixer time depends on fixer concentration, exact paper used, temperature and many other factors. There are test kits for retained silver and thiosulfate, if you want to optimize timing.
BTW this fixer does not contain thiocyanate, it should work with weak emulsions.

@John Wiegerink : in my experience, buying C-41 fixer concentrate is far cheaper than buying the raw ingredients or dedicated B&W fixer. I stopped mixing my own quick fixer formula, when I ran across a decent offer for C-41 fixer. TF-5 is optimized for fixing and washing speed, and it comes in convenient 1l bottles.
 
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Steven Lee

Steven Lee

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@Rudeofus It's not paper but regular B&W film. HP5+ FP4+ and Delta 100. This is appealing because I have a ton of this fixer but I do not develop much of C41.
 

John Wiegerink

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The MSDS gives the rough composition of this fixer concentrate. Its working solution looks extremely similar to Ryuji Suzuki's Neutral Rapid Fixer formula. 5 minutes fixer time won't hurt, but is probably longer than necessary. The ideal fixer time depends on fixer concentration, exact paper used, temperature and many other factors. There are test kits for retained silver and thiosulfate, if you want to optimize timing.
BTW this fixer does not contain thiocyanate, it should work with weak emulsions.

@John Wiegerink : in my experience, buying C-41 fixer concentrate is far cheaper than buying the raw ingredients or dedicated B&W fixer. I stopped mixing my own quick fixer formula, when I ran across a decent offer for C-41 fixer. TF-5 is optimized for fixing and washing speed, and it comes in convenient 1l bottles.

Rudeofus,
Looks like when this batch of TF-2 is gone, I'll be done mixing anymore. If it works with staining developers like Pyrocat-HD I'll have it made. Now to find a cheap source of C-41 fixer. Thanks again for the advice,
John
 

DREW WILEY

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I've been using TF4 alkaline fixer exclusively for a long time now, for both film and paper. It saves a LOT of time, and also seems to remove any residual anti-halation dye on certain films way more efficiently than conventional fixers. Great for pyro applications. No need for a second bath or HCA. I use it one-shot per recommendation, and never-reuse it. Of course, it's somewhat more expensive per volume; but what's your time worth? And what is peace of mind worth, knowing you did it right first time, every time?

Someday I should get around to comparing TF-5. But at the moment I'm in a "If it ain't broke, don't fix it" mood.
 

Rudeofus

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The thing which breaks alkaline fixers for me is paper trays. I have reasonably hard skin inside my nose and can withstand smells which many others can't, but even to me that Ammonia smell of alkaline rapid fixers is unbearable. This is, where neutral fixers really shine: they have all the advantages of alkaline fixers and they are completely odorless.

@John Wiegerink : here are my quick&dirty instructions for using C-41 fixer in a B&W setup:
  1. Most C-41 fixer is used in replenished systems, i.e. you buy replenisher concentrate, not fixer concentrate. Don't waste money on starters.
  2. C-41 process is extremely time sensitive, which means the process chain may go from (very acidic) bleach into fixer either directly or with minimal washing.
  3. This means, that replenisher diluted to working solution strength will be slightly alkaline. The product I use reaches pH somewhere between 7 and 7.5
  4. At this elevated pH the fixer will develop some Ammonia smell. If you hate this smell, take the most concentrated form of Acetic Acid you can cheaply obtain, and add dash by dash until the Ammonia smell is gone. This is when your fixer has reached the actually intended pH of around 6.5.
  5. Both working solutions and concentrate will seemingly live forever in terms of shelf life, but of course they will not have infinite capacity. It is tempting to use such a working solution indefinitely, since it "still looks good". In terms of capacity it will be no better than standard rapid fixer, so be careful.
  6. Because the working solution happily survives many months of storage, this fixer is extremely suitable for two bath fixing. If you process low volumes, put the fixer back into a tight bottle after each dark room session and use it later.
  7. For printing I have a regime developer - indicator stop - fixer 1 - fixer 2, the fixer 1 will eventually turn purple from carryover indicator dye, this is when I discard it. For film you simply count the number of rolls or do a clip test.
 

Philippe-Georges

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Anchell and Troop in "The Film Developing Cookbook" cite six advantages for alkaline fixers for film:

1. They allow shorter washing times
2. They do not dissolve image bearing silver so there is less danger of over-fixing
3.Keeping the whole developing system alkaline or neutral improves film permanence "because thiosulfate does not mordant to the image or base." (I looked up mordant at point but I can't remember what it means.)
4. Alkaline fixers have a greater capacity than acid fixers
5. They are easier to formulate and more stable than because thiosulfate is more stable in an alkaline solution.
6. Alkaline fixers can be formulated to have very low odor. (But they don't always have low odor. TF-3 does have a moderate ammonia odor.)

Acids are more difficult to be washed out of gelatine (every kitchen chef will tell you that gelatine holds acid (vinegar) very tight)...
Same for the baryta coating and the paper's fibers.
 
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