there are many varying recipes on it which difer in quantity of PI, but they function all the same - but vary in application, you have to adapt the amount of PI solution vs. the amount of fix...
One more example from Kodak, which is good for a ten times lifetime stock solution. ;-)
As promised, I digged out the report from Franz on the test - i was curious myself. Franz is a chemist, he repeated the titration five times over.
See (in german): http://phototec.de/phorum_neu/read.p...=48812&t=48812
In short and english: 500ml of 1+7 Tetenal Superfix (ordinary rapid fix), used with 5 Filmes, clearing time was 210 sec. Titration showed a silver content of 3,4g/l - WAY too much, while the clearing time indicated "good for at least another film".
Then he took a fresh fixing bath of same scheme and added silver nitrate. His results:
- PI, a 10% Solution
- 1ml of that on 10ml Fix
- prescipation at 21° ambient temp was stabile when the silver content hit the 2,8g/l mark.