GeorgK
<P class="">First of all: I always prepare my developers using boiled-down a.d. and then divide them into full, airtight PET bottles of the appropriate size, so that each aliquot is sufficient for a single development run (no partial withdrawals). For C41 developers, for example, this allows for a practically indefinite shelf life (> 1 year) when stored at room temperature in the dark. A49/Atomal, however, has always been a problem child, because even under these conditions – which are almost ideal for a home lab – the development results became unpredictable after just a few weeks; sometimes it worked, sometimes there was significant underdevelopment. It was also noticeable that a gel-like sediment became visible in the bottles after only a very short time, indicating bacterial growth.
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<P class="">I have now tried the following: into each bottle of developer, I placed a piece of exposed and developed (blackened) film leader approximately 1 cm long. The idea behind this was that A49/Atomal (especially when bottled correctly) apparently does not primarily deteriorate due to oxidation, but is sensitive to bacterial degradation. The film snippet was intended to ensure a certain concentration of silver ions, which are known to have an antibacterial effect.
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<P class="">As I’ve hardly got round to any development in recent months anyway, the bottles prepared in this way have been sitting around for over a year. Yesterday I used the developer for the first time (incidentally, there was no sign of slime), and the result was (at a 1:1 dilution) a perfectly developed CHS100-II. I wouldn’t go so far as to claim that the developer was still 100% active; I lack a direct comparison with a fresh batch for that. But based on my experience so far, that’s a very good result. At least I won’t have to worry about 1–2-month-old A49 in future.
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<P class="">Another tip: I thoroughly rinsed the (reused) bottles with household chlorine bleach before refilling them. This should prevent any bacteria that have already adapted (specialised A49 ‘eaters’, so to speak) from being carried over between batches.
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<P class="">By the way: during development in a deep tank, the continuous use naturally leads to ‘preservation’ through dissolved silver from the film.
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<P class="">We hobbyists sometimes ‘suffer’ from too low a throughput; perhaps this tip might be helpful to one or two of you when using A49 (which, whilst not a perfect developer, is nonetheless unique in certain combinations).
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Wolf_XL
...I always store my developers in Apo-Norm glass bottles. This means the A49 stock solution easily lasts for a year. However, I always use developers made from stock solutions, with the appropriate dilution, as single-use developers.
MirkoBoeddecker
I’d also put my money on the chlorine rather than the film snippet.
My last A49 was also in PET bottles (clean chemical bottles) and was from March. I last used it in December.
There might have been something in your PET bottles. Were they previously filled with fruit juice?
Best regards,
Mirko
GeorgK
The treatment of the bottles with the chlorine-based cleaner certainly plays a part. In my case, some of the bottles were reused several times, which naturally increases the risk of the problem ‘spreading’. Once bacteria that are resistant to lye and capable of metabolising the developer have taken hold, subsequent batches are, of course, very quickly ‘doomed’. And once it became clear to me that bacterial contamination was obviously the main factor behind the (in some cases) very short lifespan of the A49 in my setup, I wanted to tackle the problem from both angles to be on the safe side: firstly by preventing or reducing the initial infection, and secondly by inhibiting any potential bacterial growth; Silver ions are very effective even in the smallest concentrations (copper coins in a water bath would be a comparable example). The snippet provides a little more peace of mind and requires so little effort that it might fall under the category of ‘it doesn’t help, but it doesn’t hurt either’.
Of course, I cannot definitively judge what the main factor is now.
What matters to me is that I can now use a developer again without hesitation – a developer which, for me, is the only one that really works, for example with the Rollei 80s.
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Best regards
Georg
michael-kielgmxnet
I’ve just been reading this thread with interest. I’m also a big fan of Atomal and sometimes find myself unable to use up a batch within a couple of weeks.
I recently saw a report about water filter systems. It mentioned that some water filters release small amounts of silver ions into the water to prevent the growth of germs. Presumably, one could make use of this for Atomal too – by using filtered water for the solution. Whether the concentration of silver is sufficient is, of course, another question; after all, it must be so low that it has no adverse health effects whatsoever.
Olivinyl
Hello everyone,
I also use A49 developer in a 1+1 ratio, but only for surveillance and aerial photography films (so basically the RR80S as well). A49 is really one of the few developers that develops these film types properly without a significant increase in density from Zone 7 onwards...
I prepare my A49 with distilled water and store it in 250ml Aponorm bottles filled to the brim, which I have also rinsed out beforehand with a splash of distilled water.
After partially removing the developer, I add a squirt of lighter fluid to the bottle.
A49 lasts at least 6 months for me. I once used a bottle that was already 14 months old (filled to the brim, stored in the dark at approx. 16°C). It still worked, but I couldn’t achieve reasonable densities anymore.
I do exactly the same with Xtol. That lasts at least 12 months. (Current batch: October 2013)
No A49 or Xtol has ‘gone off’ on me yet? :rolleyes:??
Best regards, Oliver
