H O P-M T C I 115autonomy led artists and artisans involved in panel painting to adopt
techniques better fitted to local conditions, creating a change of attitude
among artists that accompanied the moral and cultural shift that is made
clear in Cennino’s Libro dell’arte. T his movement also indicated another
shift: the basis for pride in the artwork itself was no longer limited to the
achievement of creating a panel that would serve solely as a devotional
instrument in the present and near future; pride was also based on the
creation of an enduring work of art that would last for posterity.
Economic or time constraints might have encouraged the occa-
sional use of cheaper or more immediately available wood, although at
times locally available, well-known woods may have been preferred and
deliberately chosen (e.g., chestnut for the support of Guglielmo’s painted
Crocefrom the Sarzana Cathedral) (Fig. 2). In some cases, artisans may not
even have considered the implications of using different species. In report-
ing on microscopical identification of recently exhibited paintings by
Raphael, for example, Fioravanti (1994) concluded that poplar and linden
were used interchangeably by the artist.^5 It is also possible that different
woods may have been used deliberately for the sake of amusement or
experimentation; however, in the cases of complex supports or later inter-
ventions, it is likely that an artisan would simply have used any piece of
wood available in the workshop.Wood quality
There is little doubt that no matter how appropriate a wood species seems,
boards that are badly manufactured, selected, or seasoned result in unde-
sirable behavior. There is also no doubt that wood properties and behavior
were well known by the artisans who made the supports.Sawing patterns and arrangement of growth rings
Since it is well known that after seasoning, radial boards distort (cup)
much less than tangential boards (Fig. 3),^6 it has often been thought and
taught that good workmanship requires that only radial boards be used for
panel paintings. Although this is true in some cases (e.g., for oak supports
used in central and northern Europe), it does not always apply to poplar
supports in central Italy for a number of reasons.^7 Although diametrically
cut boards can be considered the optimum choice for poplar panels, they
were not absolutely required. On the one hand, a diametric board offers
two advantages: first, it is the widest board that can be obtained from a
given log, and second, it is less prone to cupping than any other board,
due to its radial cut. On the other hand, a diametric board has the disad-
vantage of containing the log’s pith, which constitutes a zone of disconti-
nuity and low strength that is prone to longitudinal cracks (Fig. 4).^8 From
an economic standpoint, since most logs were likely sawn according to a
parallel pattern, a technique that produces a high proportion of tangential
and subtangential boards, selecting only the diametric board from each log
would result in an unjustified waste of good and expensive wood material.
Another economic consideration is that a greater number oftangential
and subtangential boards result from a log that is parallel sawn.
As for the arrangement of boards according to their growth-ring
orientation, it appears that no general rule may be determined. Boards
were often arranged with the “inner” face toward the side to be painted.^9Figure 2
Guglielmo,Croce dipinta,1138. Cathedral of
Sarzana. The support of this very old cross is
made ofchestnut.
Figure 3
Drawing depicting the sawing of a log and
typical deformations ofboards after seasoning.
Only radial boards remain flat after moisture
variations.
Figure 4
Diagram showing a diametrically cut board
made weak by the presence of the pith, which
had been removed and replaced by an inset
before the ground and the paint layer were
applied. Giotto,Maestà. Uffizi Gallery,
Florence.