Shell Life of Van Dyke Sensitizer

[Sandy King <sanking@clemson.edu>]

Hi folks,

This morning I pulled out an old bottle of Brown Dyke Sensitizer, 
mixed about a year ago, that had been left for many months with a 
small quantity of sensitizer in the bottom, to a depth of about 3/4". 
What I found was a perfectly beautufly coating of silver plating on 
the inside of the bottle (but very shiny when views from the outside 
through the amber colored plastic). Given the fact that the silver 
has left the solution and formed a nice plating on the side of the 
bottle makes it pretty obvious that the shelf life of this particular 
bottle was quite a bit less than a year.

Which brings me to this question. What is the effective shell life of 
Van Dyke sensitizer, assuming that it is kept in a brown, tightly 
capped bottle, and stored at room temperature in the dark, or in very 
subdued light?

Any comments about this, or other specific information about storing 
this sensitizer, appreciated.

Sandy King