A blueish green hue can be added by spraying cupric nitrate onto the warm surface. Buff to give depth and dimension. Seal hot with Johnson's paste wax or let cool and lacquer. James, there is really only a hand full of basic patina chemicals and the variations come from combinations of mixtures and heat. Kipper's book really clearifies things.
Heat is the real key to changing the color of bronze.
I hope that I've helped, good luck with it.