Adox Adofix. A rapid fixer?

bernard_L · Jan 2, 2019

Recently I bought for the first time Adox fixer Adofix Plus. Label says "Rapid Fixer". Prepared 1+9 dilution about 3 weeks ago. Processed just 3 prints 13x18cm (5x7"). Today performed a clip test (35mm film) to establish the (almost) new condition and later monitor for exhaustion.
Clearing took just over 3 minutes. Previously, with Ilford rapid fixer, or Tetenal Superfix, the 1+9 dilution (what I use for paper for paper) passed the film clip test in just over 1 minute (fresh mix, discard when clearing time has doubled).
Does anyone have a similar or relevant experience? I wonder whether the Adox Adofix has:
- lower concentration and therefore capacity per bottle of concentrate
or..
- some different formulation, say semi-rapid(??) as a compromise to achieve other properties??

Also, this: "After opening the concentrate shall be used up within about 3 months.". Other brands may have a similar warning. I do not use up 1 litre of concentrate in 3 months. I do perform regular clip tests. Any comments, other than the stern warning "abide by the writing on the label"?

RauschenOderKorn · Jan 2, 2019

I have used Adofix Plus, but I cannot remember the clip test times. But I doubt that it was that long, because I fix film for 5 minutes only and I make sure that this is longer than 2x the clip test time.

About the 3 months: I had the concentrate sitting for more than 3 months and found sulfur precipitate in it after about 9 months. I guess Adox has factored in some uncertain storage condition.

lantau · Jan 3, 2019

Adofix Plus supposedly had a better buffer for better keeping and costs more than the previous Adofix, which had been discontinued.

I'm still on my last bottle of the non plus, which has been open for more than a year without trouble. I'll probably switch to a cheaper product or go for neutral fix for film as well.

I use 1+4 mix for film and paper. The higher dilution will not be as stable, which might be your problem. I think high dilution is for better economy at high troughput.

Martin Rickards · Jan 3, 2019

Most rapid fixer concentrates are based on 60% solution of ammonium thiosulphate and instructions are usually to dilute 1:4 or 1:5.

David Allen · Jan 3, 2019

I use it at the 1 + 7 dilution and have had no noticeable problems. However, I fix film for 6 minutes and use two-bath fixing for my prints.

The keeping properties of an open bottle are not as good as Hypam. I have had the fixer go off after the bottle was open for around 4 months. What I do now is decant the fixer into 250ml brown glass chemist’s bottles. This delivers a much longer storage life of about two years.

The reason that I use Adofix Plus is that 5000ml costs just 25€ here in Germany and 5000ml of Hypam or Tetenal Superfix Plus costs 42.90€.

Bests,

David.
www.dsallen.de

Billy Axeman · Jan 3, 2019

Here are the official recipes how to use the Adox fixers:

Adofix Plus (concentrate)
http://www.adox.de/Photo/adox-chemistry/stopbath-and-fixer/adofix/

Adofix P (powder)
http://www.adox.de/Photo/a300/

Anon Ymous · Jan 3, 2019

Martin Rickards said:
Most rapid fixer concentrates are based on 60% solution of ammonium thiosulphate and instructions are usually to dilute 1:4 or 1:5.

Their MSDS gives a 25 to 50% content of Ammonium Thiosulfate. Perhaps it has a little lower concentration.
EDIT: That's not the case, any other MSDS I looked at states a concentration of at most 50%
In any case, I wouldn't use the 1+9 dilution for films and I wouldn't use the same solution for film and prints.

AgX · Jan 3, 2019

David Allen said:
What I do now is decant the fixer into 250ml brown glass chemist’s bottles. This delivers a much longer storage life of about two years. The reason that I use Adofix Plus is that 5000ml costs just 25€ here in Germany.

That makes 20 bottles.

Billy Axeman · Jan 3, 2019

[QUOTE="... What I do now is decant the fixer into 250ml brown glass chemist’s bottles. This delivers a much longer storage life of about two years. The reason that I use Adofix Plus is that 5000ml costs just 25€ here in Germany.[/QUOTE]

If you want to go really cheap you should take the powder:

Adofix P for 1 litre: E 3,45
Adofix P for 5 litre: E 6,55

Prices in Germany (Fotoimpex).
And you can store it virtually infinitely.

Martin Rickards · Jan 3, 2019

Billy Axeman said:
[QUOTE="... What I do now is decant the fixer into 250ml brown glass chemist’s bottles. This delivers a much longer storage life of about two years. The reason that I use Adofix Plus is that 5000ml costs just 25€ here in Germany.

If you want to go really cheap you should take the powder:

Adofix P for 1 litre: E 3,45
Adofix P for 5 litre: E 6,55

Prices in Germany (Fotoimpex).
And you can store it virtually infinitely.[/QUOTE]Tthe Adofix P safety data sheet on Fotoimpex's site https://www.fotoimpex.com/shop/images/products/media/9630_4_MSDS_EN.pdf shows it to be a sodium thiosulphate based fixer and therefore not "rapid".

Martin Rickards · Jan 3, 2019

My feeling is that it is commercially not viable to make dry ammonium thiosulphate for its main use (fertiliser) and that most manufacturers sell a concentrated aqueous solution. Different manufacturers decide on different concentrations, e.g., 50 or 60% and photochem manufacturers decide on which to use and just rebottle it without doing more. Hence the small difference in dilution instructions.

lantau · Jan 3, 2019

The maximum concentration of ammonium thiosulfate in water is around 60%. That is sold as ThioSol. If you want to add a few things to make a commercial fixer concentrate you'll have to add a little water.

Doremus Scudder · Jan 3, 2019

Working solutions of fixer don't keep well for longer periods of time. Ilford gives the following for their Rapid Fixer:

"Unreplenished ILFORD RAPID FIXER working strength solutions should last for up to:
6 months in full tightly capped bottles
2 months in a tank or dish/tray with a floating lid
1 month in a half full tightly capped bottle.
7 days in an open dish/tray"

I would assume, absent any specific information from Adox, that storage life of their product would be similar. Maybe your fixer was simply stored too long. You should have done the clip test on fresh fix so that you have a base line for comparison. That's really the only way to tell if your fixer has aged past usefulness. Mix some fresh and do the clip test. Toss any fixer that takes 2x or longer to clear film than fresh fix, regardless of how much or how little you've fixed with it.

Best,

Doremus
.

Rudeofus · Jan 3, 2019

bernard_L said:
Clearing took just over 3 minutes. Previously, with Ilford rapid fixer, or Tetenal Superfix, the 1+9 dilution (what I use for paper for paper) passed the film clip test in just over 1 minute (fresh mix, discard when clearing time has doubled).

3 minutes of clearing time is definitely very long, even for 1+9 dilution. Since Sodium Thiosulfate is not all that soluble in water (AFAIK 400 g/l max), all liquid fixer concentrates sold today are based on Ammonium Thiosulfate. I would also assume, that Adofix Plus starts with an Ammonium Thiosulfate concentration somewhat comparable to other rapid fixers.

BUT: Since Adofix Plus is well buffered, a lot more Thiosulfate can decompose to Sulfate, before Sulfur precipitation becomes apparent. You won't notice aerial oxidation as much as with less well buffered fixers, but the resulting Sulfate will still slow down fixation. This might well be the explanation for the slow clearing time with freshly mixed working solution. If you want long shelf life, get a neutral or alkaline rapid fixer.

bernard_L · Jan 3, 2019

@ All; thank you for taking the time to respond.

Doremus Scudder said:
Maybe your fixer was simply stored too long. You should have done the clip test on fresh fix so that you have a base line for comparison.

The 1-liter Adofix bottle was delivered from fotoimpex 2018-05-24. It stayed intact until 2018-12-16, when I prepared 1 liter of 1+9 working solutions, one of the dilutions suggested by Adox on the label, for paper. Used it during one session (2 hours?) to fix three 5x7inch prints (did I already state this?); since then it has been stored in a 1-liter PE bottle. The bottle was closed, and the lid tightly screwed in. So now 2.5 weeks have gone by, and I perform a clip test. 3 minutes clearing time for a classical (non-tabular) film. So, OK, as a matter of principle, I should have established the clearing time at the time of initial mixing. I performed in the past systematic clip tests on Ilford and Tetenal fixer, 1+4 or 1+9, and never found a change from just sitting not three weeks, but three months or more. Consistent with the info given by Doremus Scudder. So, either Adofix has an initial clearing time longer than similar Ilford or Tetenal products, or it has degraded significantly in a full; closed bottle over a time of 2.5 weeks.

Anon Ymous said:
In any case, I wouldn't use the 1+9 dilution for films and I wouldn't use the same solution for film and prints.

Neither would I. I wrote in the OP: "Processed just 3 prints" and "Today performed a clip test (35mm film)". I don't know how to perform a clip test with paper, so I do it with a small piece of film, for the paper fixer; that is the only occasion when the paper fixer meets film.

Doremus Scudder said:
Mix some fresh and do the clip test.

Well, I just tonight mixed some 1+4 Adofix. Clearing time 45sec. The clearing time on record in my notes for fresh 1+4 Ilford rapid fixer is 25sec. Same for Tetenal Superfix. So clearing time is longer for Adox stuff, other parameters equal.

Rudeofus said:
BUT: Since Adofix Plus is well buffered, a lot more Thiosulfate can decompose to Sulfate, before Sulfur precipitation becomes apparent. You won't notice aerial oxidation as much as with less well buffered fixers, but the resulting Sulfate will still slow down fixation. This might well be the explanation for the slow clearing time with freshly mixed working solution.

Went back to lab and measured pH of Tetenal Superfix 1+4 (not freshly mixed, I'm afraid, so that is a serious procedural shortcoming); value: 4.54. Adofix 1+4: 5.67. I do not claim these values are correct to the last insignificant digit, as I did not take the time to re-calibrate my pH-meter. But I believe the difference is real.
So, thank you Roreofus, you have provided the information I was after, confirming one of the hypotheses spelt out in my initial post: "some different formulation, say semi-rapid(??) as a compromise to achieve other properties??".

Bottom line: Avoid 1+9. Use 1+4 for film (as before) and 1+7 (Adox recommendation) or 1+4 for paper. Accept the longer clearing time(s). Perform, as always, clip tests before each session to monitor the health of the fixer.

David Allen · Jan 4, 2019

AgX said:
That makes 20 bottles.

and . . . . they are cheap when ordered as a batch and significantly extend the fixer's life. I also decant Dokumal into smaller bottles to extend life during the summer when I am mainly making photographs rather than printing.

Bests,

David.
www.dsallen.de

Rudeofus · Jan 4, 2019

@bernard_L: since you have a pH meter, you could do a quick buffering test: add well defined increments of NaOH and check how quickly pH rises. Bring Adofix pH down to 4.5 with Acetic Acid first. If Adofix is indeed much better buffered, these extra buffer components may well be the culprit. As you may know, adding non-fixing ingredients to a fixer will typically slow it down. One thing which I just noticed: densities of Ammonium Thiosulfate 60% / Tetenal Superfix Plus / Adofix Plus are (according to MSDS) 1.325 / 1.33 / 1.287 g/cm3. This would confirm your suspicion, that Adofix is overall a slightly more dilute product.

PS: Only now I did notice, that Adox recommends 1+7 for paper instead of the much more common 1+9. Well, here we go ...

tezzasmall · Jan 4, 2019

I buy and then re-bottle Ilford fixer from a 5 litre container. Even when I open one of the now decanted 1 litre bottles, it lasts for months if not over a year, although I do put in a squirt of the 'gas in a tin' that some of us use. I also use a Nova slot processor and am very picky about what I print, hence a small turnover of chemicals BTW.

Ilford fixer is all that I have bought for decades. I don't know if it is cheaper or more expensive than other fixers, but I'm happy with it, so stay with it.

Terry S

AgX · Jan 4, 2019

David Allen said:
and . . . . they [20 empty bottles] are cheap when ordered as a batch and significantly extend the fixer's life.

I was not thinking of their price but of the space 20 250mm bottles of concentrate take instead the orginal 5 Liter can.
Refilling or adding inert gas is indeed something I apply.

miha · Jan 4, 2019

Rudeofus said:
SNIP One thing which I just noticed: densities of Ammonium Thiosulfate 60% / Tetenal Superfix Plus / Adofix Plus are (according to MSDS) 1.325 / 1.33 / 1.287 g/cm3. This would confirm your suspicion, that Adofix is overall a slightly more dilute product.

Interesting observation. I checked the msds of some of the most common fixers on the market, here are the numbers: Hypam: 1.34, TT Superfix Plus: 1.33, TT Superfix Odourless: 1.3, Fomafix: 1.29-1.31, Kodar Rapid Fixer: 1.32, Formulary TF-5: 1,07, Moersch ATS Alkaline: 1.45. Whether these numbers correspond to the amount of A. Thio in the solution and / or the speed of the fixing process this I don't know.

koraks · Jan 4, 2019

Other compunds will have an influence on specific gravity. For instance stuff like sulfite and boric acid, and in the case of alkaline fixers carbonates.

MattKing · Jan 4, 2019

For a period of time, if you bought Ilford Rapid Fixer with labels suggesting a 1+9 dilution for prints, the labels were quite thick.
That was because the outer labels were pasted onto older labels behind. Those older labels suggested a 1+7 dilution for prints.
The chemicals inside were identical. At the time of the change, Simon Galley (then director of Harman) posted the explanation that they had determined that both dilutions performed well, but the higher dilution improved sales.
Take from that what you will.

pentaxuser · Jan 4, 2019

MattKing said:
At the time of the change, Simon Galley (then director of Harman) posted the explanation that they had determined that both dilutions performed well, but the higher dilution improved sales.
Take from that what you will.

My memory might be a bit hazy on this change but I started printing in 2004 and cannot recall ever using anything other than 1+9 for Ilford MG developer. 1+9 may well have helped sales in that it looked like Ilford had a stronger developer but at one minute developing time at 1+9 this seems quite a conveniently short time but still delivers well developed prints so there would seem to be little or no drawback to using 1+9

pentaxuser

miha · Jan 4, 2019

Fixer, not developer Pentaxuser. However, I can't remember Ilford ever promoting 1+7, only 1+4 or 1+9 for paper. There was an error on the labeling suggesting 1+3 instead of 1+4 some years ago.

Rudeofus · Jan 4, 2019

koraks said:
Other compunds will have an influence on specific gravity. For instance stuff like sulfite and boric acid, and in the case of alkaline fixers carbonates.

Let's get an estimate for the amount of Boric Acid in Adofix Plus: the MSDS says 1-2%, which means at most 20 g/l. If we assume that these 20 g/l don't change volume of the concentrate, then they will add 0.02 to the density. The difference between Superfix Plus, Hypam and Kodak Rapid Fixer is larger than these 0.02 g/cm3.

And if Adofix Plus was loaded with extra compounds, it should be denser than Hypam. It's the other way round, though, Hypam is denser than Adofix Plus. There's a non-trivial chance, that Adofix contains less Thiosulfate per liter than other fixers and that extra water was needed to keep the buffer in solution.

PS: Ammonium Thiosulfate content is not the only criterion for a powerful fixer, see TF-5 density.

Adox Adofix. A rapid fixer?

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