Sgraffito

Sgraffito is a technique of applying two layers of medium and then scratching off the top layer to reveal the paint underneath.

Before even beginning my research I was instantly taken back to infant school where we coloured a piece of card in coloured wax crayon then went over the colour with black. Once covered, we scratched off the top layer of black wax to create colourful picture. I remember that it was a very popular and enjoyable lesson.

Sgraffito is mainly used in wall art by applying layers of tinted plaster or in pottery when applying two layers of glaze (slip) then scratching off.

An example of this technique can be seen of the facade of the Palazzo Ramirez de Montalvo, Florence built in the 16th century. The Palace was designed by architect Bartolomeo Ammannati but the facade was designed by Giorgio Vasari.

https://en.wikipedia.org/wiki/Palazzo_Ramirez_de_Montalvo

I also found the following website which shows many examples of the use of sgraffito in pottery, including a very good example of a dish with sgraffito fish by Carl Cooper.

https://www.veniceclayartists.com/the-sgraffito-fantastico/