pittyman
Dear colleagues, I’d like to ask about your experiences with the capacity of the positive fixer,
as I seem to be well below the stated capacity.
First of all: I test my fixer with potassium iodide. 10g per 100ml – normally it should be 19g – so
I’ll have to change that next time.
Current mixture 1+9 – 1 litre
With PE, I get up to about 35 sheets of 13x18 and cloudiness sets in during the test; with baryta, it starts at just under 25. Is that normal? I’ve also tried a brief intermediate rinse after stopping, as I suspected carry-over, but that didn’t help either.
The stated capacity for most fixers is 450 sheets of 18x24 per litre, which would give 45 sheets per litre of 1+9 working solution. But I’m only getting half that. :spudnikcurse:
What’s going wrong here, or are the manufacturer’s specifications too optimistic? Should I make the solution stronger, 1+4?
I’d be grateful for any helpful advice!
Best regards from the darkroom
Dirk
piu58
In principle, it makes sense to use a higher concentration of Fix. The processing time is shorter, and with baryta paper, it doesn’t penetrate the felt as deeply. I always use a 1+4 ratio and get a litre to last for 75 sheets of 18x24. I got this figure from a packet somewhere, and it has been verified (not with potassium iodide, but by measuring the clearing time of film snippets).
Your fixer is exactly half as concentrated and should therefore also last for 45 sheets. Have a go at the film snippet test.
pittyman
Hi Uwe,
I’m only familiar with the film snippet test for film fixer. Is it also useful in the positive process, and if so, how?
Are you talking about 75 sheets of baryta paper?
Best wishes from Dresden
Dirk
sputnik
I print on baryta paper and fix using Moersch’s alkaline ATS. Dilution ratio 1:5. For a 1-litre batch, I discard the solution after processing 50 sheets of 18x24. For other formats or batch sizes, you’ll just need to adjust the calculations accordingly.
piu58
> I’m only familiar with the film snip test for film fixer. Is it also useful in the positive process, and if so, how?
Measure the clearing time. You can’t see that with paper, after all. Standard cubic film should clear in a minute.
> Are you talking about 75 sheets of baryta?
No, PE. Baryta is more like 50 sheets.
pittyman
I’ve just dipped a film strip into my container of old, used fixer.
It was clear after 1 minute, but after testing it with potassium iodide, the fixer was clearly depleted,
suggesting more than 2g/l. I’m a bit unsure now. 50 sheets of 18x24 would be around 2 square metres per litre,
which is why I only managed half that with a 1+9 dilution. However, I still can’t
explain why our host’s product states a total capacity of 450 sheets of 18x24.
I still can’t explain it.
sputnik
As a child from the East who used to watch Western TV, I could never quite figure out why the housewives in the West always just happened to be holding a 5kg packet of ‘Weißer Riese’ when they were approached on the tram. :-)
bernhardmangelsgmxde
Westfernsehen isn’t helping us here. There are fixers out there that can easily fix as much material as the manufacturer promises. And they don’t have to be the most expensive products.
Personally, I bought a bottle of Adofix... and it was used up after 6 months. Well, that’s just one example, so it’s hardly representative. Now we have internet forums... and my gut feeling is that Adofix has been the culprit for years whenever people report that they don’t get sufficient fixing despite using it correctly, or wonder why they have a clearing time of six minutes with fresh fixer, or, as noted here, find that they can only fix half as much paper as stated.
Whether Adofix is simply consistently inferior to other products, or whether the quality is actually fine and there are just the odd bad bottles now and then, I can’t say, but I don’t think there’s any need to argue that there’s something wrong with the stuff, at least at times. Is fixer such a complex product that it can’t be manufactured consistently to the quality promised to the buyer?
piu58
I always use Adofix. The only thing that’s ever happened to me is that the sulphur fillings went off – it was a write-off after that. Back then, though, I’d bought a canister and it’d been sitting in the cellar for at least three years.
> a few bad bottles in there
I can hardly imagine that. It’s possible that a whole batch might be off. But that would have caused quite a stir.
TiMo
Uwe, do you know how long unopened bottles last at normal room temperature?
Thanks and best regards,
Tim
Bonderer
Hello
The manufacturers know full well why there’s never a production date or best-before date on them. Customers might complain...
The batch number is turning into a bit of a joke.
I’ve been using Adofix ever since an Ilford Hypam canister—which wasn’t even half empty—went off.
But I’ve had the same issue with Adofix (only litre bottles) before. The last of five bottles started to go off about 8–10 months after purchase. The shop where I bought it said there’s sometimes a batch in there that goes off quickly.
It could also be the fridge effect: the freshest stock is pushed to the front and sold first.
The stuff is cheap, so it’s not really worth checking.
I only use it in a 1+4 dilution; 1 litre of solution is enough for a maximum of 12 films or 10–15 sheets of 24×30 baryta or RC paper – a few more, about 30 in total – though I make a 2-litre batch in the tray. For larger quantities of RC paper, I use the Thermaphot with machine fixer.
And with film, I never push it to the limit of its usability. As a beginner, I paid dearly for that. After 4–5 years, quite a few of my films were ruined. As I didn’t know why, I sent a few strips to Ilford – that’s what they were called back then.
Just to see if they could be salvaged in any way, and what happened to them? The answer was sobering: poorly and inadequately fixed. Since then, I’ve only used fixer in generous quantities and no longer used it right down to the last drop, and I’ve switched to liquid fixer only – no more powder.
One more thing on the subject of shelf life: I got a few canisters of Kodak fixer from a newspaper’s darkroom clearance sale. The stuff was, as Kodak had written on it, about 12–15 years past its sell-by date, and only the very last canister has gone off. Ilford or Adofix wouldn’t last that long.
It might have something to do with the raw materials or the manufacturing process, or perhaps Kodak concocted a special batch for the newspapers and professionals. The publishing house bought directly from Kodak for all its newspaper editorial offices.
TiMo
You’re really making me panic with all these ruined films.
Is there actually a test to check whether negatives have been fixed properly? With prints, you can always use a drop of selenium as a workaround.
Cheers, Tim
piu58
> Unopened bottles at normal room temperature
Whether unopened or opened, it doesn’t matter. Room temperature is better than the cellar; Fix tends to go off in the cold. It’s always lasted me two years at 16°C so far, but I’ve had problems with bottles kept for more than three years.
Bonderer
Hi TiMo
Don’t worry about the films. That was a powder fixer, made by Tetenal back then. You could get it at any photo shop and, as far as I can remember, it was supposed to be enough for 10 films, which I did fix. Since then I’ve been using liquid concentrate; I don’t use it all up, and I don’t leave it standing for too long either.
And if I’ve only fixed 6–7 films, I still dispose of it and don’t leave it standing for much longer. If needed, I make a fresh batch.
I didn’t do it that way back then; the fixer stood there until I’d fixed all the films, and on the odd occasion I’d end up fixing 1–2 more films because the powder didn’t dissolve properly and it would have taken too long to make a fresh batch.
Nowadays, I fix for a bit longer, rinse a bit more thoroughly and use AGFA Sistan as a long-term protector. No more problems since then.
TR
A fixer can do no more than ‘fix’ a film to a ‘blank’ state. If it can do this with a small piece of ‘classic’ black-and-white film within a minute, then one can surely assume that it is still working. If it cannot, you should simply start a fresh batch. There should be no confusion about this. I carry out appropriate clarification time tests with a small piece of ‘classic’ black-and-white film before every fixing process – whether film or paper.
TiMo
Hello Analogue,
I’ve been doing a double fix for a while now. That should always keep you on the safe side. I didn’t do it with the first few films, though, so that gave me a bit of a scare.
Thanks also for the storage tip, Uwe. Otherwise, I would have assumed that cooler was better.
