considerably limits the risks of hygrometric shock and, additionally, allows
the work to move.^18 These boxes are particularly suitable for panels that,
because of the nature oftheir wood or because of the deteriorations they
have undergone, are very fragile and reactive.Backing systems that consolidate overly thinned supports
These systems are intended to restore enough cohesion and solidity to the
work to make possible safe handling and display. The maintenance systems
described above are not appropriate for severely thinned panels, as they
require specificfixings not feasible with heavily deteriorated works. The
more homogeneous distribution of mechanical stresses obtained by gluing
a support system on the whole of the surface was a consideration that led
the Service de Restauration to develop a number of backing methods.
Materials such as inert honeycombed panels will be used as
replacement supports for the remounting of previously transferred panels,
as the rigidity of their honeycombed structure prevents any possible move-
ment of the material (Bergeon 1990:77, n. 10).
The use of square or hexagonal balsa elements cut along or across
the grain and adhered with wax-resin seems a fitting temporary solution in
certain cases (Fig. 8a, b). The low permeability of its cell walls as well as
its low density give balsa wood a stable structure with a flexibility that
enables it to absorb some of the stresses exerted by the panel. The use of
wax-resin ensures rapid and total reversibility. Application of this tech-260 Bret, Jaunard, and Mandron
ba cFigure 7a–c
Fr ans F loris, Portrait of an Old Woman,six-
teenth century. Reverse. Oil on panel, 107.7 3
83.4 cm. Musée des Beaux-Arts, Caen, France.
The panel is positioned in its frame (a), main-
tained by crosspieces fitted with compen-
satory springs. Two other panels (b, c) have
different k inds of compensatory mechanisms
with springs.