The pigment is an oil base, NOT WATER BASE, pigmant.
Water and resin/plastic dont like each other, It will fiz and ruin your casts.
You can order pigment from Micro mark. They sell a set of 8 that you can mix
and like paint and get any color you want.
You can also try Oil base paint pigments. You can get them from Home Deopt, or a hardware store.
I used these for a bit before i tried Micro MArks. HAvent gone back to the hardware store stuff since Micro Mark.