Gast
Hello everyone,
Does it actually make sense to soak the films and PE prints in AGFA Sistan (silver image stabiliser) for 1 minute after the final wash? I use it instead of a wetting agent. I haven’t had any negative experiences – but I haven’t noticed any positive effects either. But the stuff is expensive. Does anyone have any experience with this and can tell me whether I should keep using it?
Regards,
Martin
cfb_de
Hi Martin,
You can see the positive effect every day when you look at prints in the light and in the open air: they’re still in one piece :-)
Seriously though: Sistan (consisting of a wetting agent and potassium rhodanide) has a proven preservative effect on black-and-white paper prints. I certainly wouldn’t want to be without it for sales prints.
Best regards,
Franz
MehmetCati
Hi!
Unfortunately, I can’t offer any practical experience on this, but I’ve read up on it.
Excerpt from the text as follows:
>>
The protective effect of Agfa Sistan lies in the fact that the soluble silver salt formed by oxidation is precipitated as a colourless, insoluble silver salt (silver rhodanide) the moment it is formed. This forms a protective coating around the silver grain. Silver rhodanide is insensitive to light and effectively prevents oxidation-induced discolouration of the silver layer. The excellent protective effect of Sistan has been demonstrated through a variety of tests, for example by exposure to H₂O₂ or to light, heat and humidity (sun test). Black-and-white baryta and PE prints treated with Sistan exhibit significantly better, high image stability compared to untreated prints. This requires proper processing as well as correct storage of the processed materials. For archival storage, a temperature of 18–20 degrees Celsius and a relative humidity of 50–60% is recommended.
<<
As I said, I’ve never used it and haven’t really given it much thought as to whether I’d actually need it....
Regards
M.C.
CPD
Hi everyone,
I’d like to jump in with a question – perhaps a silly one. Can this actually be used to improve the archival stability of old negatives and glass plates?
I’ve actually taken up a new hobby: collecting old glass plates. I just hope it doesn’t become a fad, because at the moment you can still pick up quite a few at flea markets – alongside rummaging through bulky waste, visiting such markets is one of my passions – for a reasonable price. Unfortunately, the condition isn’t always that great. The gelatin is crumbling, and so on...
I’m going to get round to copying my treasures.
Regards, CP
P.S.: Whenever I search for Sistan online, I can’t help but smile: I know someone who wrote their postdoctoral thesis on architecture in Afghan Sistan – the book always pops up in the Google search results.
MehmetCati
Hi Martin!
I received a reply from Robert in the ‘Dry Spots’ thread on this forum, which seems to refer, amongst other things, to the preservation of older negatives.
Here is an excerpt:
<<
(...)
So it’s not a problem. Older negatives are sometimes re-watered and treated with a stabilising bath (wetting agent and 1% formalin).
(...)
Best regards,
Fotohuis RoVo
Robert
<<
As I’m not particularly interested in the subject, I didn’t ask for further details, but formalin seems to be the agent of choice here.
Unfortunately, that’s all I can say on the matter.
Regards,
M.C.
CPD
Hello Mehmet,
Isn't formalin actually quite harmful? Aren't there likely to be toxic fumes from negatives treated in this way?
Best regards,
CP
cfb_de
Hello CP,
Yes. Formalin (or rather, the formaldehyde that evaporates from this aqueous solution) isn’t exactly good for you. As with everything in life, you have to weigh up the risks.
Best regards,
Franz
Gast
Hi!
Just a random thought...:
I don’t think formalin is any ‘more dangerous’ to handle than quite a few photographic chemicals. So handle it with care!
As for fumes, it won’t be ‘that bad’. If you consider Robert’s tip, 1%....
Back in the day, quite a few chipboard units were like a mini reactor accident.
As far as I remember, formalin is formaldehyde stabilised in alcohol. Formaldehyde is said to be carcinogenic. That’s why it’s disappeared from many a Billy bookcase and many a cosmetic product.
If you treat films with it, I really don’t think it’ll cause any health problems afterwards. But one should look into what might actually be evaporating into the air (in the ppm range?).
Now, I reckon that the formaldehyde is really only meant to act as a preservative (since it used to be used in industry for preserving glue, gelatine layers and the like. Hence my conclusion).
It also preserves quite well, so it might protect the film from fungal growth and the like.
Perhaps there are other substances that aren’t as concerning and have the same effect.
I’m afraid I don’t know much about this, but perhaps our forum host has something like that on offer?
Regards
M.C.
MehmetCati
Hi!
Just a random thought...:
I don’t think formalin is any ‘more dangerous’ to handle than quite a few photographic chemicals. So handle it with care!
As for fumes, it won’t be ‘that bad’. If you consider Robert’s tip, 1%....
Back in the day, quite a few chipboard units were like a mini reactor accident.
As far as I remember, formalin is formaldehyde stabilised in alcohol. Formaldehyde is said to be carcinogenic. That’s why it’s disappeared from many a Billy bookcase and many a cosmetic product.
If you treat films with it, I really don’t think it’ll cause any health problems afterwards. But one should look into what might actually be evaporating into the air (in the ppm range?).
Now, I reckon that the formaldehyde is really only meant to act as a preservative (since it used to be used in industry for preserving glue, gelatine layers and the like. Hence my conclusion).
It also works quite well as a preservative, so it might protect the film from fungal growth and the like.
Perhaps there are other substances that aren’t as concerning and have the same effect.
I’m afraid I don’t know much about this, but perhaps our forum host has something like that on offer?
Regards
M.C.
CPD
Hi Franz,
Does that mean that if I store the records/films in a room where I don’t live, sleep, cook or work, my life expectancy won’t drop significantly?
Best regards
CP
MehmetCati
Hi!
Here’s something that gives an idea of the expected lifespan:
>>
(...) For example, detergents, cleaning products and care products must not contain more than 0.2% formaldehyde, whilst chipboard and furniture made from it must contain no more than 0.1 ppm formaldehyde. (...)
<<
This is from the MEYER encyclopaedia, 8th edition, 2001.
And I thought formaldehyde was completely banned in shower gel...
So unless you’re actually sleeping on the treated films or making designer furniture out of them...
:P
Regards
M.C.
CPD
Hi Mehmet,
I’ve only just seen your post. I can still remember the story about the chipboard very well, and how, in our first semesters, we were still being taught about asbestos in structural engineering – that changed abruptly!
I’m not one for hysteria either, but I know that my ex (a biologist), who also carried out dissections, was absolutely terrified of the stuff. Mind you, she probably worked with higher concentrations.
I reckon if I set up my negative/slide archive in a separate room as described above, it’ll be fine – I’m not planning on throwing any archive parties, after all.
Regards, CP
MehmetCati
Hi CP!
Yeah, yeah, good old asbestos (car brakes, clutches, etc., etc.).
It was a bit like that with a lot of things, wasn’t it? Just think of that lovely-smelling benzene (in petrol) :P
Ah, those were the days...
But seriously:
I don’t consider the treated negatives to be ‘dangerous’ either.
But perhaps you could use a ‘professional’ alternative product from a photography shop(?).
Here are a few lines from www.wikipedia.de.
>>
Formaldehyde can cause allergies, skin, respiratory or eye irritation if used improperly. It is suspected of being carcinogenic; however, numerous epidemiological studies have failed to identify an increased risk of cancer. Nevertheless, according to the DFG Senate Commission for the Assessment of Substances Harmful to Health, formaldehyde is currently classified as a substance with a reasonable suspicion of carcinogenic potential (IIIB). One reason for this is that formaldehyde has been shown to have a carcinogenic effect in animal experiments with rats, albeit only at extremely high concentrations of 6 ml/m³ or more. Such concentrations would be unbearable for humans even after a short time: increasing discomfort, watery eyes, and irritation of the eyes, nose and throat would make it impossible to remain in such a contaminated environment. Acute danger to life (toxic pulmonary oedema, pneumonia) exists from a concentration of 30 ml/m³.
Certain materials containing formaldehyde (wood-based materials, floor coverings, textiles and others) can cause contamination of the air we breathe in enclosed spaces through off-gassing. In the 1980s, chipboard and plywood in particular, which were manufactured using aminoplasts as binders, came under scrutiny in this context. Today, however, formaldehyde-free wood-based materials and furniture are widely available in shops.
Certain carbamide-formaldehyde resins can also continue to release formaldehyde into the ambient air for years.
Another major source of formaldehyde emissions is incomplete combustion. This occurs, for example, in the combustion engines of motor vehicles, in foundries and during the manufacture of plastic products. Smoking also produces formaldehyde in this way, which contributes significantly to air pollution. The total smoke from a single cigarette contains around 1.5 mg of formaldehyde.
<<
Cheers...
Regards
M.C.
fotohuisrovo
Yes, CP,
Your life expectancy will be shortened if you add a 1% formalin solution to the Stabibad.
Thank you very much for the explanations about formaldehyde.
As with all chemicals, there is of course a certain risk involved. Your chemist will certainly be able to explain this better. Unfortunately, there are still no good alternatives for fungus-free archiving.
1 litre of Stabibad and 1% formalin is made using 25–27 ml of a 37% formaldehyde solution and a wetting agent.
Of course, 37% is not without risk.
But compared to a potassium dichromate solution for, say, nice clean trays B), our tip is still fairly safe.
Formalin is in the same category as, for example, hydroquinone. If you’d rather not use it, you can of course also use a developer containing, for example, ascorbic acid. For formalin, use I.P.A., but that is certainly less effective.
Eye protection, gloves and very good ventilation are essential when using 37% formaldehyde. :P
We are, of course, always available to answer any further questions.
Best regards,
Robert
cfb_de
Hello CP,
To come back to your question: under the environmental conditions you’ve described for yourself (not for the panels), you’re unlikely to come to any harm. The dose of acrolein from a single annual portion of chips is probably more dangerous.
It’s a different story for the panels. It’s not enough for them to be kept in the dark in a separate room. They also need the temperature and humidity to be controlled and kept constant.
[Personal note: Personally, I couldn’t care less about all this fuss about evil formaldehyde. I don’t bathe in it, and the truly nasty fumes from the cheap socialist chipboard of the 1980s in the West haven’t caused me – or my sister, who was a newborn at the time – any harmful side effects whatsoever. Anyone who has a problem with this should please seek medical advice and trust their doctor or pastor. But please don’t go spreading doomsday prophecies from an ecological perspective on random web forums; there is no basis for them and no medical or even scientific evidence. Just air the place out and remember: anything that stinks is, by definition, unhealthy or toxic. Whether it’s a fart, tear gas or photochemistry.]
Best regards,
Franz
Gast
Hello Franz,
According to what you’ve said, Sitan contains potassium rhodanide.
Do I need to take any special precautions when using it?
I have the final rinse tray sitting on a rack in the bath. Afterwards, the prints go into the Sitan tray next to it. Once drained (any remaining liquid goes down the drain), the prints are hung up to dry. I handle them without gloves.
After 50 18x24 prints, the remaining Sitan also goes down the drain. Am I being negligent?
Thanks for your opinion.
Regards,
Martin
cfb_de
Hi Martin,
Although you’re basically ignoring everything you’re supposed to bear in mind when working in a laboratory, I don’t necessarily think that’s negligent in this case.
Best regards,
Franz
Gast
Hi Franz,
What exactly am I doing wrong? Do I need to dispose of the Sistan as hazardous waste?
Or am I not allowed to hang up the prints? :-)
I always thought I wasn’t doing my photo lab work entirely wrong :-)
Regards, Martin
cfb_de
Hi Martin,
> Work is being carried out without gloves.
Take that, for example :P
And remember afterwards that the bath needs a scrub before you get in yourself (using the bath as a chemical drip tray or sink isn’t exactly in line with GLP either).
Best regards,
Franz
CPD
Hi,
I asked at the chemist’s, where I was told that formalin isn’t available over the counter. Oh well, I’ve got other sources too :P
Regards, CP
