I just read a great article in the latest Glass Craftsman magazine,Issue # 216! It is called “How to Make Powder Color Charts for Glass Fusing” by Linda Steider. I have always wanted to take a class with Linda Steider, but couldn’t , being on the east coast and not being able to go to Glass Craft & Bead Expo.(Someday I will) A complete description of materials, powders, base glass(white, French vanilla and black) ,set up and firing schedule is given, then you have some great samples to refer to. Thank you Linda! This answered my question of how to prepare color bars! Karen