I feel that I must come in on this one, I use liver of sulphur
ie:Potassium Sulphide to obtain the wonderful iridescent colours when
brushed onto clean silver and plunged into clean water as soon as the
shade required is reached.
I drop a few chips of the sulphur into a jar containing only a
desert spoon of water, it will dissolve in a couple of minutes this
has a shelf life of only 12 hours after which it will not give
instant bright results. In view of this I am completely mystified as
to why you say you have purchased it in solution?
The addition of ammonia will extend the life a little but I have
never added it.
The warning on the bottle to keep it away from acids is to my mind
is one of those obvious things that you would not do anyway.
For the best colouring results make sure you do not touch the
surface to be treated with your fingers as the slight amount of
grease will spoil the results,
best of luck.