There is disclosed a method for the imprinting and decorating rotomolded products. The method comprises the application to the interior surfaces of the mold of a viscous suspension of pigment in a preselected pattern. The suspension is applied to the mold surface in an oil carrier using a vegetable, animal or mineral oil that is inert under the molding conditions and that has a sufficient viscosity at the molding conditions to maintain the film on the mold surfaces. The pattern of the pigment suspension is applied by spraying, brushing, screen printing and the like and, after its application, the conventional rotomolding can be practiced. In this method, the powdered plastic, typically high density polyethylene, in powder form is charged to the mold, the mold is closed and placed in an oven heated to from 500.degree. F. to about 800.degree. F. while rotating the mold along two axes, to tumble the plastic powder against the heated side of the mold where the powder consolidates into an integral molded wall of a plastic shape. The invention provides a very high line or character definition preferably using finely subdivided pigments.