Hi folks,
I stated before that salt will not fix photographic film, but I was wrong. Yes, I tested it and it didn't work, but under special circumstances you can use kitchen salt as a fixer. So how to?
You must use a highly concentrated solution of table salt of about 300 g/l. That's a lot! That's really a lot!!! Maximum solubility is 359 g/l, so the suggested solution is almost saturated and the diluting process takes some time and/or a lot of stirring. Furthermore the fixing takes a lot of time, after about 24 hours the exposed at room light but undeveloped little piece of APX100 was clear. Since fixing time is said to have to be doubble of the clearing time, expect a total fixing time of 2 days! Rising the temperature to 30 or 40 °C will shorten the time to a couple of hours, but I don't want to "cook" my bw-films.
The perfect clear snippet of the film then was developed and no blackening at all occured, indicating that no silver halide was hold back in the emulsion. I developed with Caffenol-C-M and the film snippet got a remarkable brown tint. I noticed before that some films have a stronger brown tint if they are developed with salt as a restrainer, of course with much less salt. But of course usually the negs are first developed and then fixed, so I expect no problems.
I tried regular non-iodized table salt and iodized table salt, both work about the same. Both contain a small amount of anti-caking agent: E 535 aka hexacyanoferrat(II). Since the amount is very small - max. 20 mg/kg - I don't think it has an influence. But never say never again, hahaha.
So it's good to know that there is an alternative to thiosulphate based fixers. Be it if you live abroad or can't get regular fixer for what reason ever or simply because you like it, it's good to know. I will continue fixing with the regular one because it only takes a few minutes, but NEVER SAY NEVER AGAIN.
All these insights I owe Sir Henrique the "Cronocrator" and his fine blog: http://caffenolcolor.blogspot.de/ and the corresponding discussion in "the new Caffenol home" group at flickr. Thank you very much, guys.
Some questions are left, f.e. we have no explanation why it works and how other films behave, especially films like TMax or Delta. So before using this method you should make own trials with the film and salt you use before you ruin important negs. It's simple. Cut a small piece from the leader of 35 mm film, put it in a solution of 300 g/l salt, wait and see. Should be done in a simple glass mug.
Now after so much salt I urgently need a COFFEE!!!
Best - Reinhold
13 comments:
I thank you for the statement, I also don't have any explanation for the fact. My first result was also after 24 hours to be clear. I only have until now a report of a girl in Berlin that «fixed» in 3 days may be the temperature too low.
Cheers!
Thank you for posting. I knew you could not stay away ;-) A great option here and something to have some fun with for a trial.
I'll be busy with a book project over the summer but in the fall I'm going to use some tanks I just acquired. It will be nice to get back to some film again. Vielen Dank!
Makes me laugh, but well done :-)
which film did you use for this test?
Hi Dirk,
it was APX100 as mentioned in the post ;-) (wer lesen kann ist klar im Vorteil) :-D
Reinhold, have you considered electroplating using the cast off fixer? This would bring the silver out of solution before disposal. I would use a battery charger rather than a battery though -it wouldn't do to go to all the trouble of saving the silver and then pollute the world with dead batteries.
With a little planning you could even create a silver plated memento of your photography.
Thank you for your work here, it is a wonderful resource!
mike eubanks
The "Cronocrator" mentions in his blog that ammonia can work as a fixer. So I bought some common "Salmiakk" used in norway for cleaning bathrooms. It is not salmiak but 5-10% ammonium in water. I could not get this to clear the test strip completely but then I added salt (with iodine) to saturation, almost 300g/l.
It cleared in about 20 minutes, constant agitation at about 20 deg. Tried it on a caffenol developed film, and at 40 min it seems to be working as well as the "Plain fixer" I usually use.
By the way, be careful not to stick your nose anywhere near this fixer. As you open the tank the vapors has quite a sting and could be harmful. Handle at arms length.
Salmiakk is a household product, but it is still dangerous. Whatever you do keep it away from bleach. The vapors formed could kill you, and it may boil and spray toxic liquid.
Hein
I'm happy to have a nontoxic developer. I won't use ammonia nor electrolytic recycling. Both methods are at least really stinky or really dangerous. With electrolysis you have to control the process very exact or you may produce toxic H2S.
ALWAYS know what you are doing! If not: hands off!
@ anonymous of June 30, 2012 6:53 PM:
Glas cleaner containing ammonia doesn't work, already tried too. I used Ammonia sold for industrial use at a drugstore but doesn't know how much percent, it stinks like pest. So this was made at the balcony, fresh air. In wikipedia it says:
«... silver chloride (AgCl) is soluble in dilute (2M) ammonia solution, silver bromide (AgBr) is only soluble in concentrated ammonia solution, whereas silver iodide (AgI) is insoluble in aqueous ammonia.»
And, according to my observations, after you fix with ammonia, you still have a kind of fog, not all salts are dissolved.
With kitchen salt, temperature and concentration may reduce the fixing time to just 3 hours. Salt produces very transparent negatives, even better than thiosulfate itself.
That about ammonia is just a curiosity. Good to know just in case. Even salt is not a professional thing, also just in case. Historicaly, salt was replaced by thiosulfate for the advantages in processing time.
Reinhold,
Thanks for the precise instructions.
How many rolls of film could one fix with salt fixer before its spent?
Also, how do you dispose of your salt water fixer after use?
Sorry, I don't know how many films you can fix in salt fixer, I only used it one time to verify that it works. And TMaxes are reported to fail or they may need exessive time.
Dispose as a regular fixer, the silver from the films is toxic, not the fixer himself.
Thanks Reinhold :)
I've tried fixing with Tudor film but twice it hasn't worked. What are the special circumstance that take the salt solution to work? It might be because I didn't leave it for long enough...
Thanks for the instructions!
I tried this couple months back with a roll of T-max film that had been forgotten in my camera for couple of years. I developed it with Caffenol-C-M, rinsed with clean water and then soaked it in highly concentrated salt water (30-40 degrees celsius) for maybe about 3 hours. After that time film had completely cleared out and fixed. Left it hanging in the sunlight for month and a half, in which time it showed no colour change whatsoever, so I like to think that the saltwater as a fixer was a success.
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