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   by the great flood of 1966 in

Florence than by both World Wars combined. Many paintings

and other artifacts were submerged in the floodwaters for more

than eighteen hours. They were covered with mud mixed with heavy

deposits of heating oil that had seeped from the storage tanks housed in the

many basements of the city. The worst damage was done to the large num-

ber of panel paintings in Florence and the surrounding countryside; those

that had been submerged swelled many inches beyond their original size.

Subsequently, these paintings were subjected to a long and gradual

drying process, first in the limonaia,the old hothouses built by the Medici

in the Boboli Gardens for their favorite collection of citrus plants. These

hothouses were quickly converted into one large humidity chamber. The

humidity was raised to 95% at a temperature of 12 °C over a two-year

period. Afterward, the treatment was continued in the former army bar-

racks of the Fortezza da Basso, which in the meantime had been trans-

formed into the largest restoration laboratory in the world; it had, in fact,

become an independent governmental department, a soprintendenza,by

special decree.

Despite the carefully controlled drying process, many of the panels

shrank considerably. This shrinkage caused severe blistering and cupping of

the paint layers, as well as deformation of the supports (Cianfanelli, Ciani

Passeri, and Rossi Scarzanella 1992). Consequently, many of the panel

paintings had to be transferred to canvases and to new, rigid supports. The

oil deposits wereremoved with a poultice made from Shellsol A and talc

applied to a Japanese-tissue interleaf.

The devastation caused by the flood was, to some degree, offset

by the benefit of the better understanding that was gained about the

behavior ofwooden artifacts—panel paintings in particular. For instance,

the negative effects of dovetails, which had already gone out of style by

the end of the 1950s, were confirmed (see Rothe, “Critical History,”

herein). The negative effects of rigid restraints or crossbars in relation to

the natural flexibility of panels were better understood. It became clear

that those restraints that held the panels in place but did not hinder their

need to expand and contract were the most effective.

It also became obvious that the materials that were used for

crossbars had to be stable and unaffected by environmental fluctuations.

Mansonia,which had been widely used in Florence by the restoration

Florentine Structural Stabilization Techniques

Andrea Rothe and Giovanni Marussich