Sodium Thiosulphate (Hypo) - Lifetime

[Shangheye]

Does anyone know what the lifetime is of a 10% solution of Hypo? I have done some fixing of a couple of salt prints and then poured the solution back in the bottle (like I do with Rapid fixer) for re-use later. IS that OK...or should I be treating it as one-shot fixer? How can I test its suitability for re-use (eg some form of clearing test like for rapid fixer).

Rgds

Kal

 

[Tom A]

If it is a pure Hypo-solution (no sodium sulfite), then its lifetime is max 24 hour.
So use it and throw it away.

Tom

 

[Shangheye]

It's pure, so thanks for the pointer. Rgds, Kal

 

[ntenny]

Does hypo dissolve well in propylene glycol, I wonder? The CRC says it's soluble in ammonia and insoluble in alcohol, but has no position on glycol. If it was amenable to a preservative solution the same way that phenidone is, that'd be convenient. (I assume ammonia wouldn't be a useful solvent for this purpose.)

-NT

 

[dancqu]

Does anyone know what the lifetime is of
a 10% solution of Hypo? Kal

I regularly use straight S. Thio. at 1% to 2%
strength for fixing prints. Strength depends on
paper; fixer requirements vary. One-shot. Dan

 

[Paul Verizzo]

I regularly use straight S. Thio. at 1% to 2%
strength for fixing prints. Strength depends on
paper; fixer requirements vary. One-shot. Dan

How long do you fix with that ratio? Twenty grams is about 1/10th of the usual minimum. And then there is the matter of how many prints will it fix.

Inquiring minds want to know.

 

[dancqu]

How long do you fix with that ratio?
Twenty grams is about 1/10th of the usual minimum.
And then there is the matter of how many prints will it fix.
Inquiring minds want to know.

I fix for 31/2 to 4 minutes. A single fix at such a high
dilution is all that is needed for greatest LE. The usual
strength of a sodium thiosulfate anhydrous fixer is
150 to 160 grams per liter; 15 to 16 percent. So,
1% for Slavich, 10 grams per liter. Good for 3
8x10s, each in 1/3 liter. Dan

 

[Schlapp]

Would welcome some thoughts as to why my Vandykes bleach out a bit when fixing in straight Hypo/sodium thiosulfate. I was under the impression that Vandykes should get darker! And yes, they do seem to be fixed