Reeves-Gouache Paints. Gouache is an opaque water color that has been used traditionally by designers and graphic artists to create posters and other advertising materials. However, because of their strong, opaque colors and versatility they have also become extremely popular with artists. Reeves Gouache is ideal for teaching color mixing theory. This package contains twenty-four 10mL tubes of watercolor paints in a variety of colors. Conforms to ASTM D4236. Imported.