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?
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.
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 ...
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.
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...
It would be interesting to see if rock salt would work - at $0.02/lb [50 ton minimum, though].
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.
Originally Posted by zsas
Correct and he used this process many times.
Originally Posted by Gerald C Koch
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.
Yes, and his stabilized prints/negatives are fading and can only be viewed under very dim light for short periods of time.
Originally Posted by cliveh