Thanks for the tip Magic,

The MSDS for Platinum ll lists the following ingredients:

Sodium Sulphite
Dimezone-S
Potassium Carbonate
Hydroquinone
Sodium Bromide
Versene
Non-hazardous ingredients (whatever that may be....water?)

Now, I guess the proportions would need to be worked out.

Versene? what the heck is Versene?

Oh well, back to Google....