Gum Paste, Petal Paste or Flower Paste
Flower Paste is used for molding fine flowers and other decorations and is more suitable for decorations which may not be consumed for a while. To achieve a delicate effect the paste must be rolled to the thickness of parchment. The paste dries very quickly when exposed to the air and it is important that all paste not in use is well sealed and stored in a dry place. Liquid, paste or edible dusting powder colorings and flavorings can be blended in to the petal or flower paste. Once set this paste is very brittle.
Gum paste recipes vary but typically involve gum tragacanth, making it not as sturdy as pastillage. Because of the added gum, the dough is very elastic and soft, making it able to be rolled out thinner and worked with longer than pastillage. Both will hold up fairly well in humidity, but gum paste will soften slightly, as it will if it touches buttercream (because of its fat content) or is refrigerated.
Pastillage can be made different ways and dries hard and crisp. It is used to make bases, supports, stands and replicas. It can also be colored or painted. You have to work very quickly because pastillage dries quickly.