The back side of the panel
While the back sides of many panels are often painted, finished, or treated
in some way, the backs of others show no evidence of previous surface
treatment or painting. This condition may have been a deliberate decision
or simply a loss over time of the original treatment.Aesthetics of the back side
Some panels, particularly crucifixes, were decorated on the back side
because they were intended to be seen from both sides because of their
placement (on iconostases, for example) or use in religious ceremonies.
With other panels, the back sides have been carefully finished and shaped,
even though they probably were not intended to be as visible to the public
as was the main painting. This treatment indicates an intention to create a
work that would be lovely in itself.
Other panels were occasionally painted on both faces. In some
cases, the two faces held the same “rank” (e.g., Beccafumi’s Catalettoor
Duccio’s Maestàin Siena, which was sawn across its thickness in the eigh-
teenth century). In other cases, the painting on the back face served more
as decoration and was possibly made by another artist. Examples include
Raphael’s portraits Agnolo Doniand Maddalena Doni,which bear mono-
chrome paintings on their back faces, possibly by a disciple of Raphael;
Piero della Francesca’s portraits Federico da Montefeltroand Battista Sforza,
which bear the Trionfion the back; and a large triptych (347 3 393 cm) by
Rossello di Jacopo Franchi that bears a gesso ground layer on the back
with a painted geometrical decoration simulating polychrome marbles,
suggesting that it may have been part of a chapel (Dal Poggetto 1981).
From the technological point of view, such double-face panels are more
stable because of their mechanical and hygroscopic symmetry (Uzielli
1994). The crossbeams, if they exist at all, are confined at the periphery
ofthe support and possibly include the frame, or they may simply be part
ofthe decoration.
Some of the surface treatments of the backs of panels that are
discussed below fulfilled an aesthetic function as well.Surface treatments of the back side
The back sides of panels were sometimes smoothed and treated with
certain substances to obtain various results, which might have included
the slowing of moisture exchange, protection from the accumulation of
dust, preventive action against insects, or an aesthetic finish. As for other
features of the supports, treatment of the backs (and of the edges of
panels) was generally more frequent and careful in the earlier than in the
later centuries.
Anumber of substances were used for treating the back face.
These included a gesso grosso ground layer, which enhanced the symme-
try between the two sides, hence improving dimensional stability and the
flatness of the panel (Fig. 27). A superficial layer of red lead (i.e., minium-
red tetroxide of lead that had both an aesthetic effect and a preservative
action against insects) or white lead (basic carbonate of lead), with glue or
oil used as binding agent, was also employed, as were earth pigments.^37
It should be noted that the mixtures ofwaxes occasionally found
on the back of some panels (penetrating the wood only up to a limited
depth) have perhaps been applied in later conservation attempts.128 Uzielli
Figure 27
Beccafumi, Trittico della Trinità, reverse,
detail.Pinacoteca Nazionale, Siena. The
back ofa panel covered with the original
gesso grosso ground.