Quote Originally Posted by gainer View Post
If we put in bisulfite or the British bisulphite along with KOH our film will see K2SO3.
That's the theory & practice but Metabisulphite is not Bisulphite and something more happens when it's dissolved, there's far more free SO2

True Bisulphite (powder) can only be bought as a lab reagent and it's unstable.