How steep is fixer exhaustion curve?

[Duggbug]

I had a liter of Ilford Rapid Fixer working solution from a few weeks ago. Tested ok. I printed about ten 8x10 sheets, and afterwards tested it again and it showed cloudy: exhausted.

Are the last prints toast? Or is there some leeway with the definition of “exhausted”?

 

[randyB]

They should be ok. You can always mix up some fresh fixer and re-fix the prints. I have not had much luck with the Ilford rapid fixer, it works ok for a few weeks and then starts to sulfur-out, Of course I don't know how long the concentrate sat on the dealer's shelf. I have also had Kodak rapid fix concentrate and working solution go bad--sulfur-out-- but it was rather old--1.5 years old. I now mix powder fix for film and prints..

 

[halfaman]

Precipitates on hypo check does not indicate explicitely fixer exhaustion, but it is not far away. You can perform a silver retention test on your prints with sodium sulfide (Kodak ST-1) to check if they are properly fixed.