Saltwater as fixer

[Jerevan]

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..

 

[Muihlinn]

I think you've read about using saltwater as an efficient washing agent instead of using it as fixer.

 

[DarkroomExperimente]

I've heard the saltwater as fixer thing too ( independent of the washing use )...I also read that it either never worked very well at all anyway, and/or won't work at all with modern films

the only "household" chemical I know of that might work would be the stuff you add to your aquarium to get rid of chlorine...I think that has sodium/ammonium thiosulfate in it

 

[Jerevan]

Yes, I think I've read too much about Henry Fox Talbot lately... Looked it up now; he used saltwater as fixer first, but with little success. Later on, John Herschel suggested the use of hypo to fix pictures.

 

[ath]

You might want to read this thread on pn.

 

[Jerevan]

Yup, one myth down - several more to go...

 

[Michel Hardy-Vallée]

Hey, I just deleted my post because I realized you were asking about NaCl as a fixing agent, while I was referring to NaCl as a hypo-clearing agent, so it wasn't applicable to your question!

 

[zsas]

Apug's own (Reinhold) posted this on his blog recently that high amounts of salt (300g/l) and time (2-3 days) will clear film:

http://caffenol.blogspot.com/2012/04/fixer-2-errare-humanum-est.html?m=0

Might have to try this out, I have a spare plastic reel/tank that might work. I wouldn't test with my nice Hewes as the idea of ss in water for days worries me. Also wonder if the emulsion might float off the base after such a long soak

 

[albada]

Also wonder if the emulsion might float off the base after such a long soak

That's how it clears the film!

Mark Overton

 

[Gerald C Koch]

Fox Talbot used salt as a stablilizer not as a fixer. In this respect he was only partially successful in preventing his images from degrading with exposure to light.

 

[Bill Burk]

I thought I saw saltwater as fixer in a military context, like survival training so if you are captured you can improvise and forge a passport. Something like that, where the image only needs to last long enough to get you out of there. Does seawater work for that?

 

[Paul Howell]

As I recall durning WWII the navy washed prints on board ships using salt water and noticed that prints washed in salt water held up better than prints washed in tap water. The result was hypoclearning agent. When I lived in Southern Italy a block from the sea I washed fiber based prints in the ocean, but them in a mesh bag in a cove with not too much wave action and washed a couple of hours, 30 years later just fine. I did finish with a fresh water soak.

 

[removed account4]

hi bill

the navy used sea water as a wash-aid to rinse out the fixer, the sulphites in the water grabbed the silver ions
and dragged it out of the film and paper and rinse solution. perma wash, fix remover &c are offshoots of
the seawater-thing the navy did ( or so i have been told).

there is a person on flickr who makes a super saturated salt solutions and claims+shows that over extended time
it will fix his film. ( hours and days not minutes ).
it makes sense seeing talbot used a super saturated solution to remove residual silver from his talbotypes, and since
a super saturated salt solution can also precipitate silver from a fixer solution when mixed into it.
( hypo chek is a salt solution .. kindasorta ).
when i get around to it, i hope to see if i can somehow fix or stabilize my lumen prints using salt water ..
( mortons table salt ) and maybe if i can find it cheap enough, sea salt since it has other "stuff" in it.
but i think that it will just turn the paper white, like regular old fix ...

 

[Rudeofus]

Microdol X supposedly used NaCl as silver solvent, so obviously sea water does something to silver halides. It is well known that silver chloride forms soluble complexes with extra chloride ions, and a huge load of chloride ions like from the solution suggested on that caffenol blog could do just that.

There are a few issues, though:

• Most modern film emulsions don't use silver chloride, but a mix of silver bromide and iodide. Fixing of these is much trickier than fixing silver chloride because silver bromide/iodide is much less soluble.
• Making concentrated NaCl fixer usually means table salt + tap water, and table salt usually contains some iodide. I have seen 1g/l iodide (forms soluble AgI2- complexes) in some ultra rapid fixer recipes, but optimal amount may be tricky. Using the wrong amount of iodide might convert somewhat soluble AgCl into completely insoluble AgI.
• Saying it cleared film doesn't automatically imply archival fixing. Even if the film looks great today, who knows what it will look like a year from now? If NaCl is the only option at a given moment, I'd still keep the film somewhere dark and I would definitely refix it after return to civilization.

 

[zsas]

I shot a roll of PanF+, developed in Caffenol-C, then fixed for 3 days in a fix of 300g of Kosher salt in 1L water. It worked, the neg did clear (mostly), there is a little bit of base fog that does clear completely when a test part of the neg was put in a commercial fixer (Hypam), but I would say that a salt water fix does work if you have 3 days or so and have $ to spend on salt that is actually way more expensive than good ol' commercial grade fixed. A box of a Kosher salt was $4 for about 453g, so this is hardly a economical solution, but possible....

Neg scan of frame dev Caffenol-C and fixed in 300g Kosher salt to 1L distilled water for 3 days (this is not the frame I mention above that I subsequently put in Hypan):

I chose Kosher salt due to having no iodine as mentioned above by Rudeofus that too much iodine can adversely affect...

 

[Nicholas Lindan]

It would be interesting to see if rock salt would work - at $0.02/lb [50 ton minimum, though].

 

[Rudeofus]

I shot a roll of PanF+, developed in Caffenol-C, then fixed for 3 days in a fix of 300g of Kosher salt in 1L water. It worked, the neg did clear (mostly), there is a little bit of base fog that does clear completely when a test part of the neg was put in a commercial fixer (Hypam), but I would say that a salt water fix does work if you have 3 days or so and have $ to spend on salt that is actually way more expensive than good ol' commercial grade fixed. A box of a Kosher salt was $4 for about 453g, so this is hardly a economical solution, but possible....

And as Nicholas suggested, there should be cheaper sources of NaCl sans NaI. I guess right now the long fixing time plus the visibly incomplete fixing are the strongest issues with NaCl fixer, but two part fixing could improve at least the latter one. One possible modification could be splitting the 300g of salt into a 250g and a 50g (or 200g and 100g) quantity and running two fixer steps. Since two part fixing supposedly works miracles with regular fixer, it might improve the results from this improvised fixer without costing extra.

 

[cliveh]

Fox Talbot used salt as a stablilizer not as a fixer. In this respect he was only partially successful in preventing his images from degrading with exposure to light.

Correct and he used this process many times.

 

[Alan Johnson]

Since fixing took 3 days in 300g/L sodium chloride solution maybe seawater 30g/L sodium chloride might work in a a couple of weeks or a month.

 

[Gerald C Koch]

Correct and he used this process many times.

Yes, and his stabilized prints/negatives are fading and can only be viewed under very dim light for short periods of time.

 

[hjesus]

Hi, everybody! I found this discussion by chance only. But I think I may contribute with some experiments I made. A few years ago I restarted doing film photography like in the old times. I realized then that there were now alternative processes like Caffenol, Caffenol and vit. C and some other discoveries in what concerns B&W developers. But, for my surprise, nobody was trying to find an alternative to the fixer bath. Then I started investigating on that and I found some alternatives. The first one I found was concentrated Ammonia. It works, it is fast, but may not fix all films and the fumes are terrible. I made that a couple of times at my balcony. Reading more, I realized that before Herschel's proposal of Sodium Thiosulfate, salt was used in a very concentrated solution and warm. So, one night I made the more concentrated solution I could of salt, warm and put a small stripe of film in it, maybe Fomapan 100, I think. After waiting several minutes and nothing happened, I went to sleep. Next day, just for curiosity, I took a look to the stripe and... it was totally clear, as fixed with thiosulfate. I published this result at the Caffenol Group in Flickr and there was a big discussion and resistance. I met Reinhold G. (http://caffenol.blogspot.de) because he first denied the fact and later published «Errare humanum est», where he agrees with me that salt may fix films.

My first recipe was to use 300 g salt per liter, only and 24 hours at room temperature or less if one uses temperatures above room temperature.

But yes, some films like T grain films resisted for days until they were (bad) fixed with salt.

All this happened in Spring/Summer of 2012!

Meanwhile, the subject has been sleeping and nobody was really interested in it. But now things are changing and I decided to improve this surprising fixer. I discovered 3 things that makes it better:

1. The salt solution should be filtered with coffee filter. This filtering will retain impurities and also small salt crystals that will induce a fast recrystallization that may damage the film producing small holes in it.

2. A few amount of Potassium Bromide (2-4g/l) will also delay salt crystallization for more than 48 hours and speeds the fixing to some hours less but not much.

3. A very small amount of household bleach (Sodium Hypochlorite) will reduce the fixing time to just a few hours at room temperature for common films and about 10 hours for T-Grain films. I have a household bleach that says <5% Sodium Hypochlorite and from it I use 2 ml/liter. So it is really a very small amount. Even so, the solution will turn slightly yellow (what indicates that some Chlor is released).

Another possible alternative, other than salt:

Potassium Metabisulfite and Sulfur are easy to find in farming shops, they are used in wine making. With these two stuffs one may prepare Potassium Thiosulfate, another good alternative fixer.

As Recipe, dissolve 100 g of Potassium Metabisulfite in 1 liter of water, put in a stainless steel kettle and bring it to boil. Add 10 g of Sulfur and let it boil in low fire for several minutes. You will end with about 500 ml of liquid. Filter the unreacted Sulfur with coffee filter and use as fixer. It takes about 2 hours to completely fix. I think that a very small amount of metabisulfite reacts with Sulfur to give Thiosulfate and so the fixer is slow compared with regular fixers of Sodium and Ammonium Thiosulfate.

For more, visit me at http://caffenolcolor.blogspot.pt

 

[Rudeofus]

Interesting recipes, allow me to add a few notes:

- About house hold bleach speeding up fixation time: my explanation would be that the Hypochlorite oxidizes Iodide ions to Iodate, and that Silver Iodate is much more water soluble than Silver Iodide. Since there won't be much free Iodide in solution at any given time, this process can be expected to be slow, but apparently faster than fixation of AgI in NaCl.

- About home brew Thiosulfate: Metabisulfite is quite acidic, and I can hardly imagine the Sulphur Dioxide smell you had to endure when you boiled 100 g/l Potassium Metabisulfite. Please be aware that Sulphur Dioxide is quite toxic. Also, as you probably know, acidic environment is not exactly conductive to Thiosulfate formation, so your yield must have been abysmal. Try to add Lye to this mix until it does no longer reek to high heaven, and try to get more Sulphur into the process: one mol of Potassium Metabisulfite (222g) will consume two mol of Sulphur (2*32g = 64g) to form two mol Thiosulfate. Typical concentrations for fixing film are between 0.7 and 1 M Thiosulfate.

- You will not be able to combine house hold bleach and Thiosulfate, as the former will oxidise the latter before it has a chance to see free Iodide. With some bad luck you will release Hydrogen Sulphide and Chlorine in the process, both of which are very toxic. Generally speaking, house hold bleach is not a safe or harmless chemical compound, and very unsuitable for random experiments IMHO.

 

[hjesus]

Hi, thanks for the feedback!

You are quite right in all 3 points. I will comment them, only:

- I knew that house hold bleach attacks the emulsion, already tried it alone and the result was a totally blank acetate stripe. Thus the idea of using a very small amount. I am speaking of 2 ml per liter!!!

- Yes, it is quite acidic but both metabisulfite and sulfur are easy to get and they react but not too much. No, boiling metabisulfite didn't produce that much gases and I always switch the fumes extractor on. Don't be affraid, I always check theoretically what may be produced before. In fact, using Sulfite instead of metabisulfite would be better and as you say, by adding lye we will produce sulfite from metabisulfite and so, that is a good suggestion.

- Yes, very well said, bleach is a hazardous stuff to be used with care. Look here : http://www.buzzfeed.com/peggy/16-common-product-combinations-you-should-never-mix#.xs3a2DEOM

 

[Rudeofus]

One thing you may look out for is the effect of water impurities on the activity of Hypochlorite. Like many other redox reactions, the decomposition of Hypochlorite is accelerated by iron and copper impurities commonly found in water. The amount of impurities will determine the decay rate of Hypochlorite and as a result the aggressiveness of the bleach. The maximum amount of bleach you can add to your brine without destroying your film will therefore be highly variable.

 

[cliveh]

Yes, and his stabilized prints/negatives are fading and can only be viewed under very dim light for short periods of time.

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.