Tempera Paint Cakes can be used on paper, postcards or any surface which accepts temperas. After dipping brush in to clean water, stir paint brush on top of tempera cakes to liquefy and activate pigmets before paintings. Stir more to add deeper color pigmet and opacity. Includes six 2 1/2" x 3/4" tempera cakes. Paints is reusable after drying on cakes. Non toxic.