In pastels, sgraffito refers to the technique of scraping through a layer or layers of color to reveal underlying color (often the white or light color of the base surface/paper)

It is called "sgraffito" the Italian word for scratch.

Leonardo da vinci used sgraffito in some of his work (in italian, graffiato) and the famous children's author/illustrator/artist Eric Carle (The very hungry caterpillar)

Sgraffito

The term 'graffiti' derives from the Greek graphein ('to write'). Graffiti (sing. graffito) or SGRAFFITO, meaning a drawing or scribbling on a flat surface