Flower Myth by Paul Klee, 1918. Watercolor on pastel foundation on fabric on newsprint on board.
Resist techniques in art use the incompatibility of two mediums to create layered effects with color and texture.
Children often discover resist techniques by experimenting with watercolor paints and crayons on paper. The wax crayon repels watercolor paint that is brushed over it; the watercolor paint adheres to the paper surrounding the crayon. Artists create designs with pastels and watercolors, scratching out the pastel once the watercolor has dried to reveal the paint-free paper beneath. Other mediums can be used in similar resist techniques.