Panel Painting - Panel Construction and Preparation

Panel Construction and Preparation

The technique is known to us through Cennino Cennini's The Craftsman's Handbook (Il libro dell' arte) published in 1390, and other sources. It changed little over the centuries. It was a laborious and painstaking process:

1. A carpenter would construct a solid wood piece the size of the panel needed. Usually a radial cut piece was preferred (across rather than along the length of the tree; the opposite of most timber cuts), with the outer sapwood excluded. In Italy it was usually seasoned poplar, willow or linden. It would be planed and sanded and if needed, joined with other pieces to obtain the desired size and shape.
2. The wood would be coated with a mixture of animal-skin glues and resin and covered with linen (the mixture and linen combination was known as a "size"); this might be done by a specialist, or in the artists studio.
3. Once the size had dried, layer upon layer of gesso would be applied, each layer sanded down before the next applied, sometimes as many as 15 layers, before a smooth hard surface emerged, not unlike ivory. This stage was not necessarily done after the 16th century, or darker grounds were used.