Adofix precipitates

removedacct2 · Apr 10, 2021

I use whatever fixer is available. Typically Foma or Ilford in liquid concentrates or powder giving reusable stock solutions with 1+4.

One and half month ago I got chemicals from a girl who briefly tried home development, a basic set with Rodinal, Adofix and Adoflo, ~90% full, a bit only had been used. Superficial visual inspection was ok, no precipitates, fog nor miscoloration, and I have used quite some of the Rodinal, no issue. I had enough mixed stock fixer already so the Adofix stood in the fridge. This morning I was to mix some of that Adofix, but ... solid residues, mostly all along the side of the bottle that was against the back wall of the fridge, ie. colder, yet not freezing. I shaked it well after I let it warm at room temperature, but these are precipitates, so I will just discard it:

this fixer is the one with blue label, not orange, my bottle says "Adofix" and currently on Adox site its label is "Adoxfix Plus", no idea if the "Plus" is just naming or if there's a difference:
https://www.adox.de/Photo/adox-chemie/adox-stopp-und-fixierbaeder/adofix/

on Fotoimpex site the fixer is orange label:
https://www.fotoimpex.de/shop/fotochemie/adox-adofix-plus-expressfixierer-500-ml-konzentrat.html

radiant · Apr 10, 2021

antonio_b said:
, mostly all along the side of the bottle that was against the back wall of the fridge, ie. colder, yet not freezing.

First of all you should contact Adox / Fotoimpex on this first rather writing here.

Second: you have probably frozen it and that is below storage temperature (5-30 deg C). Freezers back walls are typically below zero celcius.

koraks · Apr 10, 2021

Lower temperatures can promote precipitation. High temperatures can accelerate breakdown of thiosulfate generating solid sulfur. Low pH levels do the same. In fact, it's quite remarkable that most fixer takes at least a few months to break down into a sorry mess at all!
Don't fret over it. Next time just keep the fix out of the fridge and enjoy it while it lasts. If you're dissatisfied with a particular product, try another one.
FWIW: most decomposed fix I've tried still fixed fine although of course with reduced capacity.

removedacct2 · Apr 10, 2021

I didn't notice Fotoimpex does mention on their site (not on the bottle) Treten Ausfällungen oder schwefeliger Geruch auf, ist das Fixierbadkonzentrat nicht mehr einsetzbar. so their recipe is indeed probably more sensible to precipitate/flocking.

The temperature by the back of my chemicals and film fridge is around 2C/3C, so yes under the minimum 5C recommended by Adox or Ilford, yet not freezing and I had concentrate bottles of Ilford Rapid Fixer and Fomafix for months there without issues. So maybe I keep all fixers at room temperature, which is around 20C, I have a big drawer under my development sinks where I keep the citric stopper and the Fomaflo/Adoflo/Kodak Photoflo.

Usually I buy Foma or Ilford, do 1+4 stock mixes in 2x 1liter bottles, as i do double baths fixing, and always keep them in the fridge, also the concentrate. I often look on local listings for chemicals and film resold (if cheap) by people who tried film but gave up, and that's how I ended with this Adofix...

halfaman · Apr 10, 2021

In my experience putting the fixer in the fridge does not improve shelf life. Avoid high temperature or humidity is enough.

Rudeofus · Apr 10, 2021

Low temperatures slow down reactions, but increase solubility of Oxygen in water, therefore a fridge may or may not be helpful in extending shelf life of developers and fixers.

If you don't plan on high throughput, I recommend you stick with neutral or alkaline fixers, these have substantially better shelf life than acidic fixers.

removedacct2 · Apr 11, 2021

Rudeofus said:
If you don't plan on high throughput, I recommend you stick with neutral or alkaline fixers, these have substantially better shelf life than acidic fixers.

spring/sommer I usually shot a lot of BW , mix batches of 1 liter every week or less, shelf life isn't a concern, just that putting opened BW chemicals, also concentrates, in the fridge was a habit... nothing else. My opened HC-110 and Rodinal are in the fridge too....
As for acidic/alkali I never cared to learn more about it, just that sometime I used power fixers requiring longer clearing time, and these were I think natrium instead of ammonium (thiosulfate).
Only practical points I have in mind: ammonium ones work better on T-grain emulsions, doesn't attack stains of tanning developers( I use sometimes Tanol). So "rapid", ammonium based fixers seem the safe all-around ones.

anyway I have learned by experience about fixer flocking

koraks · Apr 11, 2021

antonio_b said:
So "rapid", ammonium based fixers seem the safe all-around ones.

They are. Frankly, there's very little need to resort to sodium-based fixers unless ammonium thiosulfate/rapid fixer is for some reason impossible to obtain.

Tom Kershaw · Apr 11, 2021

koraks said:
They are. Frankly, there's very little need to resort to sodium-based fixers unless ammonium thiosulfate/rapid fixer is for some reason impossible to obtain.

I just spotted that Adoxfix P II is apparently ammonium thiosulfate based even though supplied as a powder. I've always associated rapid fix with the liquid concentrate format.
http://www.adox.de/Photo/adofix-p-ii-powder-fixer/

koraks · Apr 11, 2021

Tom Kershaw said:
I've always associated rapid fix with the liquid concentrate format.

Not necessarily (as you found out). The problem with ammonium thiosulfate in its dry form is that it tends to decompose over time. This can probably be prevented by encapsulating the thiosulfate particles to prevent them being in contact with air. Encapsulation is an often applied solution to this problem, certainly in photo chemistry.

Tom Kershaw · Apr 11, 2021

koraks said:
The problem with ammonium thiosulfate in its dry form is that it tends to decompose over time.

I have tended to use Tetenal Superfix Plus recently as a UK company 'Firstcall Photographic' sells it at a very reasonable price and performance is good.
https://www.firstcall-photographic.co.uk/tetenal-superfix-plus-fixer-5-litres/p541

Rudeofus · Apr 11, 2021

koraks said:
Not necessarily (as you found out). The problem with ammonium thiosulfate in its dry form is that it tends to decompose over time. This can probably be prevented by encapsulating the thiosulfate particles to prevent them being in contact with air. Encapsulation is an often applied solution to this problem, certainly in photo chemistry.

The big question is, whether Adox can do such a thing. The easiest indicator would be their D-76 clone offering (if they have one). Companies, which can reliably encapsulate powders, can also offer single powder D-76, everyone else has to use two bags per batch.

@antonio_b : The biggest advantage of Ammonium Thiosulfate is its much better ability to keep Silver Iodide in solution. If Silver Iodide load is sufficiently high, Sodium Thiosulfate will form some insoluble Sodium Silver Iodide Thiosulfate mixed salts. Ammonium Thiosulfate doesn't do this. Many T grain emulsions are higher in Silver Iodide, but traditional emulsions (think Tri-X) may also be like this.

Leppy · Apr 11, 2021

Hi, just joined after a while away from serious amateur photography. I have some very out of date chemicals and paper (shed load). I,ve been getting rid of some old 35mm cameras I'll never use but still have 7 Nikon bodies incl an F2 and an F2a. I put a film through and the fixer (Ilford Hypam) was thick with particulates.Being a cheapskate I filtered it and mixed it. Did a fix test with a strip of exposed fp4 and it cleared in 4 mins so I fixed it for 8 mins. Seems fine but do you know about long term. I also have a more recent 2.5lt Ilford multigrade but that's very dark brown so don't think I'll waste my time with that.

koraks · Apr 11, 2021

Rudeofus said:
The big question is, whether Adox can do such a thing.

Well, the big question then becomes who actually makes the chemistry Adox sells, and if THEY can encapsulate something like amm. thiosulfate.
Btw, the plastic jar of ammonium thiosulfate I bought about 2 years ago is pretty much fine still apart from some serious caking, so perhaps Adox('s supplier) just bets on the decomposition problem not being particularly severe, just adds an anti-caking agent and calls it a day.

Tom Kershaw · Apr 11, 2021

Leppy said:
I also have a more recent 2.5lt Ilford multigrade but that's very dark brown so don't think I'll waste my time with that.

You are probably right about the Multigrade developer, very dark brown is not a good sign.

Auer · Apr 11, 2021

Tom Kershaw said:
I just spotted that Adoxfix P II is apparently ammonium thiosulfate based even though supplied as a powder. I've always associated rapid fix with the liquid concentrate format.
http://www.adox.de/Photo/adofix-p-ii-powder-fixer/

Cinestill Cf96 is powder as well, and works very well.
https://cinestillfilm.com/products/f96-bw-bleach-bypass-rapid-fixer

Adofix precipitates

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