Adele and Jarrod - I have done figurative work since about 1988, and have worked in both true bronze and in a couple of types of resin. Most "cold cast" bronzework seems to be figurative, because itís a much cheaper process and gives some access to the large figurative market.
I have watched advertisements for this material all along, and have seen some in galleries, principally during a visit to Santa Fe, New Mexico, about 6 - 7 years ago. Any careful observer will immediately distinguish between true bronze and resin with included bronze powder. All that I have seen is the regular brownish color of fresh bronze, but I have read in many places that it can be patinaed with regular patina mixtures - liver of sulfur, copper nitrate, ferric nitrate, and so on - to give green, blue, or various brown shades. Jarrod has described the usual procedure, as I have seen it published - a thin coat of the mix on the inner surface of the mold, followed with a thicker coat of resin to build up to the desired full thickness for strength.
An advantage of resins is that they can take many additives. I generally used finely chopped glass fiber, for both strength and a nice, pale green color. I no longer use resins because of either allergic reactions or toxic fumes. Some local sculptors add dry, powdered clay to the resin. That gives a sort of ceramic look.