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Fixer formula


AFAIK Agfa 304 is only mildly acidic. Acidity only comes from the small amount of potassium metabisulfite in it. Acidity is not a concern with Agfa 304.
 
  • eli griggs
  • Deleted
  • Reason: My pointless question already adressed
RalphLambrecht said:
AFAIK Agfa 304 is only mildly acidic. Acidity only comes from the small amount of potassium metabisulfite in it. Acidity is not a concern with Agfa 304.
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Not what I read:

I need a long lasting fixer solution.

Fixing too short is always worse, because this may leave poorly soluble Silver Thiosulfate salts in the emulsion, which will not wash out. This is not an attempt to contradict your statement but I was surprised at how little fixing time appears to be needed according to this video by John...
www.photrio.com
 
We can debate long about what "very acidic" means. @Rudeofus gave a concrete pH in the first post you linked to: 4. That's a normal pH for any rapid fixer. It generally creates no problems when fixing film, paper or plates.

Note also that when it comes to pH, there's the absolute value, but also the buffer strength. The relatively small amount of bisulfite in the Agfa formula makes a fairly weak buffer - so the pH may be decidedly acidic, it will easily drift upwards if e.g. developer carries over into the fixer. I say this because the qualification of "very" in conjunction with pH always carries this duality: it's about the absolute value, but also about stability.

If a more neutral fixer is desired, I always recommend using C41 color fixer. It's very fast, near neutral and fairly economical if you buy minilab quantities. This makes sense because it can be used for virtually every fixing task, so it's all you need (and indeed, virtually all I use today).
 
koraks said:
4. That's a normal pH for any rapid fixer.
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Nope. If you look at the msds for Kodak rapid fixer the concentrate pH is 5 and for Ilford rapid fixer the pH is 5.1.
It seems that Agfa 304 is more acid than normal rapid fixer. Admitted I only tried it once but it did give a cloudy deposit on re-use, unlike proprietary fixer.
 
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Little surprise it's acidic and sulfurs out quickly: instead of 10 g/l Sodium Sulfite and 2-3 g/l Sodium Metabisulfite of my soup this Agfa 304 contains 10 g/l Potassium Metabisulfite. So that's already a bit tight on bisulfite, and then this thing is acidic to the point where Sulfur Dioxide will tend to escape over time. This may stabilize the pH for a while, but once the bisulfite is gone the fixer will go bad very quickly. Don't get me started on the potassium either ...

Well, some people seem to like it this way ....
 

making your own rapid fix has a similar economy as buying ready-made but has the benefit of always being fresh and only preparing as much as you need.
 
I have calculated TF-3 ingredients (from FDC formula ) for 1 litre working solution with ammonium thiosulfate granules (I could get ammonium thiosulfate in granular form only, here in India). The formula is as below —

1. Warm water – 600 ml.
2. Ammonium thiosulfate – 96 gms.
3. Sodium Sulfite – 12 gms.
4. Sodium Metaborate – 1 gm.
5. Water to make 1 litre.

The pH of the fresh solution is 7.6

Clearing time for PanF+ in fresh solution @ 20°C is 1 minute 25 seconds.
 
RalphLambrecht said:
making your own rapid fix has a similar economy as buying ready-made but has the benefit of always being fresh and only preparing as much as you need.
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Exactly -- and not having to worry about it "going bad".
 
I use TF-4 for negatives as I started using it when I went to PyroCat as a main developer and fell into the habit. Very stable and predictable. For printing, I've liked Ryuji Suzuki's formula and again, have just settled on it as it works and is a simple mix to do. I make 1.75 liter batches and put up in that size liquor bottles. I'll see if it pastes in a readable form here....

ammonium thiosulfate @60%
200ml​
sodium sulfite
15g​
sodium metabisulfite
5g​
water to make 1.0 liter
 

The biggest problem you will have with this formula is smell: Ammonium salts leak Ammonia gas at pH > 7. This will work well in tanks, but not in open trays for fixing prints. This is one of the advantages of Ryuji Suzuki's neutral rapid fixer (already posted here, and also present in the articles section), it's completely odorless and it has none of the issues associated with acidic fixers.

If you look at Bill Troop's fixer formulas: TF-2, TF-3, TF-4 all quite alkaline, then all of a sudden TF-5 at pH 6.5. Hint, hint, hint ...
 
RalphLambrecht said:
making your own rapid fix has a similar economy as buying ready-made but has the benefit of always being fresh and only preparing as much as you need.
Click to expand...

Making neutral fixer has the advantage of never having to obsess with freshness ever again. I have a 10l canister of Tetenal's C-41 fixer concentrate from 2020 and it still works like new. The previous canister, also from 2020, was open since 202 and was used up in the course of these 4 years.
 
I mix and use TF-2 and will probably continue to use it until I die. Just seems to work for me and I can make it easily myself. Oh, and it's fairly cheap also. Never had a problem with it using a staining developer either.
 


Not sure about the 60ml 0f sodium bisulfite.

I am mixing Kodak Fixing Bath F-24, formula from the KODAK Processing Chemicals and Formulas data booklet.

50 degrees C water 500 ml
Sodium Thiosulfate (Pentahydrate) 240g
Sodium Sulfite (Anhydrous) 10g
Sodium Bisulfite (Anhydrous) 25g
Cold water to make up to 1 litre


Suitable for films, plates, or papers when no hardening is desired.
For satisfactory use, the temperature of the developer, rinse bath and wash water should not be higher than 20 C (68 F)

Do not dilute for use.

Kodak F-24 looks very much like the formula that you found.


+++++++++++++++++++++

I found your question as I was looking for the substitute to Sodium Bisulfite. I think it is Sodium Metabisulfite. Used measure for measure.
I found a series of posts here recently, and if remember correctly the outcome was, that the Sodium Metabisulfite is interchangeable, also the Sodium bisulfite is not very stable when kept on the shelf long term.

Can anyone confirm this and possible give me a link to the conversations that I am talking about?

It could be a good idea in the future to add a label to my developer, fixer etc. with the formula of the contents.

Thank you.
 
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Kodak F-24 is an excellent choice.
Yes, bisulfite = metabisulfite for any practical pourpose...
 
Many Thanks Alessandro.
I will write it down in my book of facts for the future.
How did we manage before the internet?
 
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