1. When paper casting is dry, apply a light coat of varnish to seal the casting from moisture (so it will not swell and lose the design when paint is applied). Apply a light 2nd coat of varnish and let dry. Note: You may also apply varnish to the back of the casting for more permanence. Variation: Apply varnish only to the design and leave the outside edge unvarnished.
2. Apply paints to casting, one color at a time, and let dry between coats so that colors don't run together. Let dry.
3. Optional: Apply a light coat of spray varnish to seal in paint. Let dry. Apply a 2nd coat of varnish if desired for more sturdiness. Let dry.
4. Glue magnet to back of casting and let dry.
Casting above was painted with light blue and a medium royal blue; casting below features a navy blue and gray blue color scheme.