Interesting and surprised by fixer chemistry !?!.

[peter k.]

Had a laugh today.
Mixed some Ifford rapid fixer that a friend gave to me last year when the fixer we had, went bad with crystallization. In fact he filled another container we had full, so mixed up some today 1+4. Tested a strip of undeveloped film for a minute and it came out clear with a tint of green still on the strip. Seemed normal, but then began to wonder... and could not remember if he had given me mixed or straight. So dipped another strip into the container directly to see if it came cleared faster, but it did not even clean or clear the strip!
I'll be darned!
SHOCKED!
So for fun, took another strip and did it a minute, just in running water, and even just with water, more of the green, anti halation layer washed off then the strip we washed in the unmixed fixer. Interesting you use these chemicals for years and don't know what is really going on. Finding that water is a stronger additive then we ever thought of, when mixed with a different base, even when it over powers it 4 to 1. Mixed together as one, suddenly both can do something that neither could do before, when separated!

 

[Maris]

Straight rapid fixer is very slow because there is not enough water in it to dissolve the silver tetrathionate (water soluble!) and other fixation products. The relative paucity of water is why a bottle of rapid fixer concentrate feels very heavy for its size.

 

[Arklatexian]

Had a laugh today.
Mixed some Ifford rapid fixer that a friend gave to me last year when the fixer we had, went bad with crystallization. In fact he filled another container we had full, so mixed up some today 1+4. Tested a strip of undeveloped film for a minute and it came out clear with a tint of green still on the strip. Seemed normal, but then began to wonder... and could not remember if he had given me mixed or straight. So dipped another strip into the container directly to see if it came cleared faster, but it did not even clean or clear the strip!
I'll be darned!
SHOCKED!
So for fun, took another strip and did it a minute, just in running water, and even just with water, more of the green, anti halation layer washed off then the strip we washed in the unmixed fixer. Interesting you use these chemicals for years and don't know what is really going on. Finding that water is a stronger additive then we ever thought of, when mixed with a different base, even when it over powers it 4 to 1. Mixed together as one, suddenly both can do something that neither could do before, when separated!

In biology we called that symbiosis!........Regards!

 

[Rudeofus]

This is prominently discussed in Mees's "Theory of the Photographic Process", available as free&legal PDF from here. Look at page 520 and following. Typical rapid fixer concentrates are 40-60% Ammonium Thiosulfate plus other stuff.