Color the flat craft material with wax crayons. The colors and designs you use will show up when you scratch off the black acrylic paint. Color rainbow shapes for an appealing children’s project, or use white crayon exclusively for a stark black and white finished product. Coat the material with several layers of crayon and press down hard to distribute a generous amount of wax.
Buff the waxed surface with a clean rag to remove some of the wax. This will make it less resistant to paint.
Cover the entire waxed surface with black acrylic paint, using a paintbrush. Allow the paint to dry thoroughly before scratching.
Scratch off the paint with nails or your favorite scratching tool to reveal the color underneath.