Joe;

It is 5/169.9 to give moles of silver. Once you have that, you use 248 x 25% to get the quantity of sulfur and use that at X mg / mole for the emulsions in my book. Of course I have used 100 mg of Sodium Thiosulfate Pentahydrate per mole which is not exactly 100 mg/mole. It is less than that.

PE