The Structural Conservation of Panel Paintings

(Amelia) #1
noteven visible in the new radiograph. The approximate positioning of
the fragments outside the lower left and right of the oval was now clear.
Enough new information was now available to consider returning the
painting to a lunette format. The respective museums agreed not only
to turn the Washington picture permanently into this format but also
to remove the addition from the Metropolitan picture and to abut the
two pictures one above the other in a single frame made specifically for
theexhibition.

The removal of the addition on the Metropolitan picture was relatively
straightforward. The panel had been thinned to approximately 1 cm
overall and heavily cradled (Fig. 4), and while many splits and surface dis-
tortions were present (Fig. 5), the panel showed no signs of recent move-
ment. It was, therefore, decided to remove only as much of the cradle as
was necessary to facilitate the removal of the addition. The grain of the
addition was oriented horizontally, while that of the original panel was
vertical. Close examination of the joint revealed an extremely asymmetri-
cal tongue-and-groove joint (Fig. 6a). The upper lip of the groove section
measured less than 1 mm thick, which is an unlikely configuration. It was
speculated that this must have originally been a symmetrical joint, the sec-
tions ofwhich measured 5, 6, and 5 mm, for a total of 16 mm (Fig. 6b),
which is still too thin for an Italian poplar panel of this size. Based on
comparison with other unthinned Sienese panels of this period and date,
it seems more likely that the original thickness was between 2 and 2.5 cm.
Once the panel was cut in two, it may have seemed unnecessarily thick. At
this point, it was probably partially thinned (to 16 mm), and the addition,
with a symmetrical joint, was added. At some later date, after slight warp-
ing, the panel and the addition were further thinned, probably to obtain a
flat surface for the application of the cradle, leaving what for all practical
purposes was a half-lap joint.

Removal of the
Metropolitan Addition

T   N  F  G M 345

Figure 4, below
Reverse of the Metropolitan Nativity. The
joint ofthe cross-grain addition can be seen
just belowthe first crosspiece from the top.


Figure 5
Raking light photograph clearly showing
splits and distortions in the Metropolitan
panel and the smooth surface of the addition.
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