Quote Originally Posted by Relayer View Post
commercial reasons is interesting, but not reply to my question - why Agfa-304 use mix Sodium Thiosulfate and Ammonium thiosulfate in approx 1:1 proportion instead of complete reaction?
It's an old formula, before ammonium thiosulphate was available. It doesn't need to be a complete reaction the Ammonium ions help with the solubility of the silver thiosulphate reaction which in turn releases Ammonium & Chloride ions again which means it doesn'y need to be added as a 1:1 proportion.

Ian