Fixing in table salt solution
I developed 2 test strips of Agfaphoto APX 100 for the same times in Fomadon Excel (similar to Xtol) at 23.5C.
One strip was stopped and fixed normally in proprietary chemicals.
The second strip was stopped with one wash of water at 27C then fixed for 24hrs @ 28 +/- 2 C in a solution comprising 150grams table salt in 600ml water.
The tank was kept in a warm cupboard (hot water cylinder) and agitated about every 2hrs except during 8 hrs when it was only agitated once.
The print from the negative fixed in table salt solution is entirely satisfactory but held side by side with a print from the proprietary fixer negative it is slightly more grainy.
See scans of 0.1 in square sections of negative, processed identically.
Interesting experiment. Apart from the apparent extra graininess, can you be sure that table salt has actually fixed the film permanently in the way that proprietary fixer does?
Why would you want to spend 24hours agitating every 2 hours to fix your film. It's not like buying fixer that will do the job in 5 minutes is expensive.
I'm not familiar with the early work but here it is stated that Fox Talbot used a concentrated salt solution for fixing in his early work so yes I think fixing would be permanent:
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love this stuff
from what i remember talbot's salt fixer sometimes wasn't permanent, sometimes it worked, and othertimes he had "troubles" ...
( that is why he was turned on to hypo ) ..
what i was told about the salt fixer is that it "preserves" the image, and sometimes it doesn't, or fix it completely. i wish i could remember who told me
and where i read it, i'd link to it for you.
i think its great to have materials to light-fast things
and develop things that are in a lot of kitchens ... the darkroomexpermente did all sorts of tests
and developed film in shallots, as well as rosemary and also what seemed to be dinner ( salad )
now with a little salt its fixed
I wonder if this would be useful for preserving solargraphs? Standard fixer pretty much ruins the image completely, and unfixed they are doomed to slowly fade away...
Hi Alan, it may also depend on the structure/composition of the silver halide crystals. Silver chloride is more readily dissolved than silver bromide, which is more readily dissolved than silver iodide. For example, sodium sulfite can fix a silver chloride emulsion, but might take very long to fix silver bromide, and might not be able to dissolve silver iodide or bromo-iodide. Apparently even sodium thiosulfate is quite inefficient at dissolving silver iodide (which may explain - at least in part - why sodium thiosulfate isn't recommended for fixing t-grain films etc.). Adsorbed dyes and other emulsion additives likely play a role as well.
Michael, but sodium thiosulfate is recommended for fixing T-grain films.
isn't ammonium thiosulfate usually recommended ( speed fixer ) for t grained films,
and fix times can sometimes still seem excessive in order to get the color tinge out of the film.
(tmy, tmx and tmz at least )