Page "Tempera" Paragraph 17

Tempera adheres best to an absorbent ground that has a lower " oil " content than the tempera binder used ( the traditional rule of thumb is " fat over lean ", and never the other way around ).

The ground traditionally used is inflexible Italian gesso, and the substrate is usually rigid as well.

Historically wood panels were used as the substrate, and more recently un-tempered masonite and modern composite boards have been employed.

Heavy paper is also used.