The Structural Conservation of Panel Paintings

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penter specific dir ections, even on subjects relating to the manufacture of

the support. In Duccio’s Maestà,for example, the aesthetic interaction

between painting and front frame suggests an intervention by both artist

and carpenter, even if such was not provided for by the contract.

In some cases, a specific ar tist would have had his own carpenter

or would have consistently used the services of the same bottega. For

example, the same hand may be recognized in several supports of Giotto’s

paintings, including the Maestà di Ognissantiand the Crocifisso di Santa Maria

Novella. Filippo Lippi and Sandro Botticelli also had exceptional carpenters.

Ground layers

Up to the fourteenth century, great care was used in preparing the ground

layer, which, as described by Cennino, was basically made of glue, cloth,

gesso grosso, andgesso sottile. T he cloth, generally made of large, overlap-

ping pieces, was often applied not only over the whole panel but over the

engaged frame as well (see Fig. 1).^2

In the fifteenth century, cloth strips were often applied only on

themost sensitive areas (such as joints between boards, or knots and other

defects in the wood), whereas in later years parchment or vegetable fibers

mixed with glue were used. Increasingly, less care was devoted to gessoing.

Correctly chosen and applied cloth created the best results; even

in cases where wood movement caused the whole complex of cloth

together with the ground layer to separate from the wood, the painting

often remained well preserved. In contrast, parchment tended to detach

extensively and lift at the edges.Likewise, vegetable fibers did not perform

as strongly and efficiently as does the woven structure of cloth. The

absence ofcloth and the limited care applied to the ground layer resulted

in a greater likelihood that wood movement would affect the paint layer,

which then suffered from characteristic damage, such as lifting and corru-

gation into numerous small crests.

The selection of wood species for panels

Although it is customary to think of “supports made of wood,” it would

be more precise to refer to “supports made from one or more wood

Figure 1
Giotto,Crocifisso di Santa Maria Novella.
Church of Santa Maria Novella, Florence.
Coarse and thin cloth glued on planking and
on frame moldings.