Adding color to resin is easy to do...ETI has Transparent and Opaque Dyes that make it easy...here's how:
Mix your resin according to manufacturers instructions and pick the color you would like to use.
Simply add a small amount and mix into the resin.
Pour into molds...
Use a lighter to remove any bubbles that rise to the top. Let dry 24 hours...
Now you have wonderful resin pieces to use in projects.