AFlemish oak panel of original thickness had two nonoriginal
metal battens screwed to the back (Fig. 8a–c). Not surprisingly, the panel
developed splits and disjoins. A chalky, weak ground, combined with
restrained wood movement, had caused tented flaking and losses. The
battens were removed to prevent further damage while the painting
awaited treatment.
To remove the battens, the panel was laid horizontally for better
control. There was concern that release of the battens might cause a sud-
den warp movement and precipitate further flaking. A temporary frame-
work was built to allow the panel to assume an unrestrained shape, as well
as to provide support, improved access, and secure handling (Fig. 8d).
Wood may be preferred for such temporary supports, since a basic
framework can be built quickly and easily. An adjustable, reusable, and
therefore economical alternative was built from wood and right-angled-
section metal girders, slotted for bolted assembly.^18 Asmaller honeycomb-
core panel was bolted to the middle of the framework to preserve some
access from below and to decrease twist.
Adjustable levelers, made from machine bolts threaded into brass
plates, were attached to the framework crossbars in a regular pattern
(Fig. 8e). The levelers were turned against flexible wooden battens that
conformed to the panel back. As the metal battens were removed, the lev-
elers were periodically readjusted to maintain contact as the panel changed
shape. Fortunately, little movement occurred in this case, but the screws
were readjusted periodically as the panel equilibrated.
This type of metal girder can be used for several purposes, such as
the trolley shown in Figure 7, which was later used as a “trolley easel” to
support a large panel for treatment. The pair of rubber wheels at one end
swiveled. A central pair was fixed to roll parallel to the longer trolley axis
to allow easy maneuvering in any direction.
Mobility of such temporary supports is useful, especially in a busy
studio where large paintings must be moved often to allow photography,
passage of other large paintings, and so forth. For stationary support,
either the wheels were blocked, or the base was elevated slightly onto
wooden battens or bricks. More rigidity could be had by doubling the
girders or by adding more structure.The structure and treatment of two large panels will be compared and
contrasted because they show an instructive range of differences in period,
place oforigin, materials, construction, changes over time, deterioration,
and conservation interventions. Their similarities show much about the
structural behavior of large panels. An attempt has been made to relate
the need for treatment, and some available treatment options, to the
causes of deterioration. Some points specific to each case are included to
emphasize the individuality that bears on treatment decisions. Though
neither panel is typical, their mechanisms of change are similar to other
cases. The paintings are referred to by the artists’ names.
Figure 9a–c shows a painting by Anton Raphael Mengs (1728–79)
on walnut (Juglans regia L.) that was completed in 1771 for the chapel of
All Souls College, Oxford.^19 The use of wood of a relatively high density is
slightly puzzling for such a large panel and, moreover, one that would have
had to be transported from southern Europe.^20 Though the painting is now
about half its original thickness, its original weight may be estimated toTwo Examples of
Large Panels
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