ground drip at the edge. It is interesting to note, in relation to the origins of this panel, that
Mengs was in a transition period at the time this painting was commissioned, having just
arrived in Rome from Madrid via Florence (Roettgen 1993:30–32).
20 Such considerations did not stop others from using heavy woods for panels that were commis-
sioned from afar. Though Rubens may be cited as an example, oak was the standard panel
wood in northern Europe, so lighter woods would not have been commonly used there.
Lighter woods, mainly softwoods and poplar, were more common in Spain and Italy, and
therefore it is curious that walnut was used here.
21 Based on a density of 640 kg m^23 from Lincoln (1986:27).
22 Marco Palmezzano,The Mystic Marriage of Saint Catherine,1537. Oil and egg tempera on
poplar panel (visual identification), 2560 31805 3 20 mm thick.
23 The earliest reinforcement lattice was glued to the thinned panel with casein, an adhesive
common in Italian panels of that period (Marijnissen 1985:65) and less likely to be found as a
panel adhesive in northern Europe in the same period. This observation was subsequently
strengthened by research, kindly shared with the author by P. Balch. Known as the Calzolari
Altarpiece, the painting was commissioned for the Church of S. Agostino in Cesena, near
Palmezzano’s native Forli. The painting had been moved to the Ercolani collection in Bologna
by 1776. Cavalcaselle saw it in England in 1860, stating that it appeared “damaged [and] comes
from the Ercolani in Bologna” (Quest’opera non molto bella e danneggiata pervenne alla Raccolta
Ercolani di Bologna) (Grigioni 1956:575). Therefore, it seems likely that the earliest lattice and
some related damages are at least 120 years old, or probably nearly twice that age.
The lattice was constructed and then glued as a unitto the thinned, flattened panel. This
was evident from the dowelled cross-halving joints of the lattice, exposed during removal. The
dowels were set into tapered holes and finished flush on the unexposed side of the lattice.
24 This technique included a thick gesso ground and a combination of oil and tempera paint.
25 Most planks were cut to the taper of the tree trunk for minimal waste, and the topmost end of
one plank was positioned beside the bottommost end of its neighbor.
26 Interestingly , the cutting direction caused by the bevel of the panel maker’s chisel resulted in a
distinctly butterfly-shaped profile in many of the mortises, when viewed from the back. Thus,
it is nowpossible to mistake the mortises for original insert sockets ofthe butterfly type, with
inserts set in from the back, a technique seen in some panels.
27 Loose tenons, probably of holm oak (Quercus ilex L.) were used to align the plank edges dur-
ing assembly. Regarding origins, both woods could be found in Italy and Spain at the time. In
Spanish panels, walnut is found mainly in panels from the regions of Navarre and Castille
(Marette 1961:68). It is possible that the panel was constructed in Spain, the painting begun
there by Mengs and finished after his move to Rome.
28 This observation was not tested chemically.
29 The tenons were fitted very loosely, with at least a 3 mm gap all around. Before the joining,
the tenon glue may or may not have been allowed to dry. It is interesting that the fit is quite
free, with little contact area, suggesting that the tenons were more for alignment in assembly
than for joint strength.
30 The surfaces are rubbed together to thin the glue line until the increasing adhesive strength
makes further rubbing very difficult. For such large planks, this might have been done with
mallet blows at the plank ends while joining pressure was applied.
31 Consolidation of one damaged edge has been presented in a previous article (Brewer 1994a).
32 The filler, harder than plaster of Paris, had keyed well into the surrounding damaged wood. It
had swelled on setting, a characteristic of plaster of Paris (Gettens and Stout 1966:253).
33 After a thorough facing of the area, wood inserts of similarly grained European walnut were
applied to the Mengs. Only insect-damaged wood was removed, to within 2–3 mm of the
ground, as with the Palmezzano. Though the wood was sized with Paraloid B72, the use of
water-based glue caused considerable swelling of the higher-density walnut, which then
tended to delaminate from the back of the weakened casein ground. It was then necessary to
remove the remaining wood to the ground, which was strengthened with a thin size, and the
inserts were directly fitted.P A S C L P P 473