The Structural Conservation of Panel Paintings

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  1966 to restore the Italian primitives of the

Campana Collection in the Musée du Petit-Palais in Avignon (see

Bergeon et al., “Two Hundred Years of History in France,” herein),

several factors have influenced the evolution of the restoration of wooden

supports in the Service de Restauration des Musées de France.^1

In the wake of the 1978 Oxford congress of the International Institute for

the Conservation of Historic and Artistic Works, several studies were car-

ried out jointly with the Centre Technique du Bois (CTB) during the 1980s

to test and improve restoration methods.^2 An initial study focused on the

behavior of experimental oak boards,^3 which were painted on one or both

sides according to a technique of the masters^4 and subjected to artificial

aging in a climate-controlled room.^5 Systematic testing was conducted to

determine if the way the wood was sawn had an influence on its behavior

when it was submitted to an alternation of wet and dry cycles; results

confirmed that panels painted on both sides remained stable under varia-

tions of relative humidity (RH), whereas panels painted on one side only

showed distortions and, moreover, retained some residual distortions

throughout the entire sequence ofcycles.^6

These results led to the search for a product with a degree of per-

meability close to that of the paint layer but that would also be transpar-

ent, reversible, and applicable as a backing. A coating composed of a layer

ofgelatin and two sheets ofSaran^7 proved to be most effective, but this

isolated result has thus far not been extended into practical application.

The next study involved simulated repairs of cracks by the inser-

tion of triangular-section pieces, according to a technique developed at the

Istituto Centrale del Restauro in Rome. Some thirty test samples^8 were

submitted to accelerated aging,^9 and the best results—little distortion, no

splits or cracks—were obtained when the groove was shallow and at a 90º

angle, and the inlay was made of wood cut on the quarter.

Another study tested two methods for backing severely thinned-

down panels^10 —one with two superimposed layers of balsa-wood rectangles,

the other with two layers of cork held rigid by an inert material.^11 After

artificial aging, the cork-backed panel showed considerable distortion,

whereas the balsa-backed panel remained flat. The balsa backing was

Research

The Conservation-Restoration of Wooden

Painting Supports

Evolution of Methods and Current Research in the

Service de Restauration des Musées de France

Jacqueline Bret, Daniel Jaunard, and Patrick Mandron