Saltwater as fixer

[RalphLambrecht]

It's just one of those things I heard somewhere:

Wasn't one of the first methods of fixing paper and negatives was by using saltwater? Does anyone have any clue what kind of concentrations you'd need and if it would be possible to fix, say a roll of Tri-X in it?

If not, is there any other household stuff that could serve as fixer? Just curious..

to my knowledge,strong salt solutions were used by the pioneers of photography in the early 1800s ti fix silver emulsions with limited success prior to the invention of hypo but there is no real substitute to a properly fixed emulsion.

 

[RalphLambrecht]

Actually, I would contest this. From my own experiments and also hinted in Fox Talbot's notebooks, I believe there is a salt/silver nitrate concentration that produces a very permanent image. Hitting this is very difficult to achieve. However, after many experiments I managed this only once, but unfortunately and due to my crap notes and data recording ability I can't quantify what that combination is.

If you had done this in 1820,the invention of photography would have been yours!Don't forget itwas eventually rewarded with a government pension.

 

[Gerald C Koch]

https://en.wikipedia.org/wiki/Henry_Fox_Talbot

from the above article, "Talbot devised several ways of chemically stabilizing his results, making them sufficiently insensitive to further exposure"

Part of the charm of these early prints is their colors; lavender, cranberry, mauve, ... . It is these colors that are lost first on exposure to light. This and their lack of true permanence account for the fact that these prints cannot be displayed in normal light.

 

[Alan Johnson]

Gerald did call me out when I did the test in table salt:
(there was a url link here which no longer exists)
I think if the negatives were fixed for a longer time than the test I did, they should be pretty stable as silver chloride doesn't have any reaction with the atmosphere as far as I know.

 

[Arklatexian]

It's just one of those things I heard somewhere:

Wasn't one of the first methods of fixing paper and negatives was by using saltwater? Does anyone have any clue what kind of concentrations you'd need and if it would be possible to fix, say a roll of Tri-X in it?

If not, is there any other household stuff that could serve as fixer? Just curious..

While I never heard of salt water (seawater) used as a fixer, I have heard of it used as a fixer wash, (hypo clear). During World War 2, on islands in the South Pacific, fresh water was in short supply. Some of the military darkrooms found that if negatives and prints were soaked in seawater after fixing, the wash times were shortened considerably. On the basis of these experiences, Kodak and others experimented and came up with what many of us call "Hypo Clearing Agent" today. I hope this helps. Hypo in whatever form it is called, is probably too inexpensive to substitute with seawater even if it did work. They were trying to save "water" not chemicals back then.....Regards!

 

[hjesus]

You should have used 150g/500ml and the results would be much better. I already answered at your 2013 post! I didn't know about this discussion earlier! And you did right, mentioning the source at Flickr!

 

[Jerevan]

Necro posting, boys!

I have yet to see a serious, conclusive test in a laboratory setting that shows that NaCl can fix negatives permanently.

 

[pentaxuser]

Surely if it were to work just as successfully as proper fixer then considering how long the idea has existed someone by now would have done it so long ago that he could point to say 20 years or more of success.

Success breeds success and by now forums would be full of advice about using salt water as fix based on its success. An example is that we know water works instead of stop bath with film simply by the number of those using water successfully but no such evidence seems to exist for salt water as fixer.

I am afraid that I remain sceptical.

pentaxuser

 

[hjesus]

Necro posting, boys!

I have yet to see a serious, conclusive test in a laboratory setting that shows that NaCl can fix negatives permanently.

Why don't you try it yourself? Is there more seriousity than that? 300g/liter salt/Normal grain film/24 hours. Then, if some halide is in the emulsion it may be redeveloped or stained with Sodium Sulfide. Try with a virgin film and then make the redeveloping test or sulfide.

 

[Gerald C Koch]

Surely if it were to work just as successfully as proper fixer then considering how long the idea has existed someone by now would have done it so long ago that he could point to say 20 years or more of success.

+1

I think that this is the ultimate test for any "new" idea. If something were as good as postulated it would already be in use.

 

[hjesus]

Of course it is not as successful as proper fixer. It is only a curiosity and an emergency fixer for war times, desert areas and so on. Who is going to wait 24 hours when the regular fixer just needs minutes?

 

[Robert Masters]

Nothing new on this in 9 years? Following on from the experiments by Reinhold G. and hjesus, I have been trying out room temperature fixing of both film and paper with 300g/l salt.

I have been using lake salt (a common source of cooking salt here in Australia), as it is low iodine.

Multigrade appears to fix reliably in 6-8 hours at room temperatures (18C-22C), and HP5 seems to clear in about 24 hours.

So, what is going on in the chemistry? We have AgBr2 in the unexposed areas of the film. Add to this an excess of chloride ions, and they convert the AgBr2 to AgCl2. The solubility of AgCl2 is about 5 times that of AgBr2, but still not very high. Given enough time, and enough fluid, it will dissolve, or at least enough will for our purposes. Fortunately the actual amount of AgBr2 in film is not very much, and 600ml of fixer fluid is a lot of salt water. This also explains the speeding up of the process by heating.

By comparison, the solubility of Ag2SO4 is around 1000 times higher - which is why a sulphate fixer works so much faster.

Now, what happens when we add a trace of bleach to the equation?

 

[Alan Johnson]

Multigrade appears to fix reliably in 6-8 hours at room temperatures (18C-22C)

Can you clarify this claim? Was it tested by re-immersing in developer? Thanks.

 

[RalphLambrecht]

It's just one of those things I heard somewhere:

Wasn't one of the first methods of fixing paper and negatives was by using saltwater? Does anyone have any clue what kind of concentrations you'd need and if it would be possible to fix, say a roll of Tri-X in it?

If not, is there any other household stuff that could serve as fixer? Just curious..

In the early days of photography, very strong salt water solutions have been tried as fixer but, it doesn't really work. What are the invention of sodium thiosulfate, I'm going to working fixer had been found to my knowledge, there are no other household solutions that are a working alternative.

 

[Robert Masters]

Can you clarify this claim? Was it tested by re-immersing in developer? Thanks.

Not by re-developing, but by re-exposing in full sun with a mask for six hours. No variation between masked and non-masked areas were visible.

 

[Robert Masters]

In the early days of photography, very strong salt water solutions have been tried as fixer but, it doesn't really work. What are the invention of sodium thiosulfate, I'm going to working fixer had been found to my knowledge, there are no other household solutions that are a working alternative.

I will counter your claim with the extensive work by better people than I, as documented here:
http://caffenol.blogspot.com/2012/04/fixer-2-errare-humanum-est.html
http://caffenolcolor.blogspot.com/2015/08/still-about-using-salt-as-fixer-for.html

It does work, just very, very slowly. As a fallback when thiosulphates are not available (or you don't want to handle sulphate compounds), it is viable, provided you have time.

 

[MattKing]

I'm concerned about the tests in those referenced links.
I don't see any A-B tests of negatives with images - negatives in salt vs. negatives in something like Ilford Rapid Fixer.
Followed by re-development tests to check for further changes.
One of the most important criteria for an effective alternate fixer is whether it will give you the same quality of negatives as the fixers we currently prefer.

 

[Robert Masters]

@MattKing I will dispute that an alternative fixer must give the same quality of negative to be effective. What it needs to do is fix the film or paper permanently.

If it gives a different cast or different grain, or even a different level of contrast, that becomes an artistic decision, not a technical one.

Unless you mean by 'quality', ''stability'. In which case ignore everything I just said.

I will, however, debate that re-developing or re-fixing is the correct way to verify the effectiveness. Surely re-exposing is the real test, as that is what will determine if an image is stable.

 

[MattKing]

I do mean stability, but by "same quality" I also mean things like the same range of densities and level of fog, as well as physical characteristics like flexibility.
By re-developing, I mean checking for un-fixed halides by exposing the salt treated negatives to light and then putting them through another round of developer, followed by standard fixer, to check for observable changes.
If exposing to light and then further developing the salt treated negatives results in a further change, that means that the salt treatment left developable halides in the emulsion, which will eventually lead to at least further change, and more likely degradation.
To observe any such change, it is important that the negatives bear an image.

 

[Raghu Kuvempunagar]

So, what is going on in the chemistry? We have AgBr2 in the unexposed areas of the film. Add to this an excess of chloride ions, and they convert the AgBr2 to AgCl2. The solubility of AgCl2 is about 5 times that of AgBr2, but still not very high. Given enough time, and enough fluid, it will dissolve, or at least enough will for our purposes.

Silver Chloride can be removed in a minute or two by dilute (2%) Ammonia.

 

[Alan Johnson]

In one experiment, its in this thread, I found that if it is attempted to fix salted paper prints in strong sodium chloride solution they fade to a yellow color that would make them un-marketable.
https://www.photrio.com/forum/threads/fox-talbot-and-salt-fixing.141074/

But post 37 refers to working with silver bromide paper and it is possible that this may behave differently.
Still, it would be easy enough to test by attempting to redevelop.
This would be more conclusive than exposing to sunlight for a relatively short time IMO.

With regard to fixing negatives in sodium chloride solution. see post 21 here:
https://www.photrio.com/forum/threads/fixing-in-table-salt-solution.107457/

 

[Rudeofus]

So, what is going on in the chemistry? We have AgBr2 in the unexposed areas of the film. Add to this an excess of chloride ions, and they convert the AgBr2 to AgCl2. The solubility of AgCl2 is about 5 times that of AgBr2, but still not very high. Given enough time, and enough fluid, it will dissolve, or at least enough will for our purposes. Fortunately the actual amount of AgBr2 in film is not very much, and 600ml of fixer fluid is a lot of salt water. This also explains the speeding up of the process by heating.

By comparison, the solubility of Ag2SO4 is around 1000 times higher - which is why a sulphate fixer works so much faster.

There is no AgBr2 to be found in film emulsion, you probably meant AgBr. What an excess of Chloride ions does: it creates higher level complexes of the (AgCln)(n+1)- kind, which may be both tight enough to remain stable in the presence of Br- and water soluble. Note, that this will hold to a much lower degree in the presence of iodide ions, therefore you "cleared" film may not at all be free of residual Silver Iodide.

Sulfate will not form such complexes and will therefore not work at all for fixing film There are tropical developers with 100 g/l Sodium Sulfate, and no solvent property has ever been reported, this is simply not how the chemistry works.