straight (Wolters 1952:9). Wider slots, made with saws, were normally
filled with small strips or wedges of wood to keep the panel straight
(Zillich 1991:46–50).Flattening by cradling
Many panel paintings are cradled from earlier conservation treatments.
Cradling was the normal procedure after double-sided paintings were split;
it was also the classic system used to reinforce thinned panel painting sup-
ports. Cradle systems are well known and widely published; therefore, the
technical details of particular cradling systems will not be described.Cross cleats or lattice systems of the eighteenth and nineteenth centuries
In Germany, Austria, and Switzerland, cradle systems were not used until
the eighteenth century. An early method to maintain the flatness of panels
involved setting cross cleats into the support (Fig. 13). Lucanus did not
adhere to the method of gluing or screwing slats to the panel reverse, as he
stated that slats or cross cleats are not necessary for small panels and are
ineffective for huge panels (Fig. 14) (Lucanus 1832:116). Köster recom-
mended a movable system of two slats laid across the grain (Köster
1828:13). Hampel described movable cross cleats, left loose without adhe-
sive joins in a dovetail halved joint (Hampel 1846:22). A 1912 restoration
reportfrom the Alte Pinakothek in Munich summarized all problems with
rigid slats fixed across the grain of the panels. Such slats were removed
from many Gothic and Renaissance panel paintings to set the wood of the
panels free (Kinkelin 1912:fol. 8). Brachertdiscussed cross-cleat systems and
their disadvantages, as did Straub (Brachert 1955b:15; Straub 1963:153).
Starting in the eighteenth century, rigid wooden frameworks and
lattices were mounted on the reverses of panels to reinforce them (Zillich
1991:59). Therewere many early treatments that preceded movable cradles.
Many such rigid frameworks and lattices mounted on panel paintings were
well documented in the Kunsthalle Karlsruhe before they were removed
during this century (Koch 1981:passim). These simple but potentially216 Schiessl
Figure 13, right
Lucas Cranach the Elder, Mary with the Child,
ca. 1518. Rev erse (photographed during the
1950s). Oil on limewood panel, 345 3 226 cm.
Kunsthalle Karlsruhe (inv. 108). The very
small and thin panel was probably glued in
the eighteenth century onto a rigid cradle
that was obviously originally a canvas
stretcher with crossed reinforcements. Traces
and drops of glue can be clearly seen.
Figure 14, far right
Master of the Bamberg Altar, Legend of Saint
Wolfgang,ca. 1490. Reverse. Oil on panel,
6753 375 cm. Kunsthalle Karlsruhe (inv. 54).
This photograph from the 1950s shows the
conservation treatment of the nineteenth cen-
tury. All the edges were cut, and four strong
cross braces of oak were adhered to keep the
painting flat.