Jack Richeson's Tempera Watercolor Blocks are a convenient source of brilliant opaque watercolor and can be used again and again! The blocks of solid, hardened paint are ideal for distribution and collection in the classroom, and will not deteriorate in storage. With the addition of water, their color is instantly usable. Simply apply water to a block, work the color with a brush to a smooth consistency, and apply to an absorbant surface. Appropriate colors can also be mixed to produce beautiful intermediate hues! The blocks come in Large, Small, and Mini sizes. For even more variety, choose matte or metallic!"