You don't measure so little you make up a 1% or 10% solution (of the Pentahydrate equivalent).
Are you sure the 0.2g per 1000ml/litre isn't the typo, usually the sodium Thiosulphate is used in the First Developer for reversal at between 4 to 12g per litre. Actually Potassium Thiocyanate is more commonly used.
A 10% solution of Pentahydrate would be 100g in 1 litre, 1% 10g per litre, so with Anhydrous that's 63.7g per litre for 10%, 6.37g/l for 1%.
I'd mix 10%, then i it's 10x in ml the dry weight in gms, so the 0.2g would require 2ml. 10% Thiousulphate solution is always handy for Farmers reducer etc.
Just checked and it is in the region of 0.2-0.3g/l Thioslphate in RA-4 reversal so not a typo.
Ian
Last edited by Lostlabours; 25th April 2020 at 07:52 AM.
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