The Structural Conservation of Panel Paintings

The intarsia panels, and indeed the entire room, had sustained damage

from the studiolo’s four-hundred-year tenure at the Gubbio palace, espe-

cially in those years when the palace was neglected and abandoned. The

ducal palace housed a candle factory near the end of the nineteenth cen-

tury. Paul Laspeyres, who saw the studiolo in its original location in 1873,

described it nine years later as being in a “severely deteriorated state.”^13

The Lancellotti and Loewi restorations had aged, and many of their inter-

ventions had become visible. Woodworm infestation had substantially

deteriorated the supports, and they had lost structural strength.^14 In areas,

the back panels and matrix sections had separated, and in a number of

locations, the inlay was loose and protruding from the matrix sections.

Also, many of the restorations were discolored. In some instances wood

replacements had been selected without respect for either grain direction

or the proper species. Thin rosewood (Dalbergiaspp.)^15 veneer, for

example, was used to restore areas that should have been restored with

brown oak or bog oak.

The intarsia images were cleaned with a variety of gentle cleaning emul-

sions containing hydrocarbon solvent, water, and soap.^16 Athin layer of

7.5% shellac was applied to the surface to saturate the wood colors and

serve as a retouching varnish.^17 Intarsia elements that had become

detached were reglued with traditional warm protein glue (hide glue).

Discolored restorations were toned with either watercolor or dilute

Golden acrylic color to create a balance with the aged fifteenth-century

intarsia. Missing elements were replaced with wood, which was carefully

selected with a concern for the proper species and for similarity in texture,

gr ain direction, hue, and density.

Afew of the intarsia images had no back supports and needed

elaborate intervention to restore their structural strength. The state of

each detached intarsia varied from panel to panel. Some panels had no

remaining hardware at all, while in others the original nails had been

clipped, and stubs ranging from 0.5 to 1.0 cm in length protruded from

theback of the matrix sections. The intarsia panels that still possessed

their original supports had survived well over the last five hundred years

because ofthe flexibility inherent in the original nailing system. Therefore,

it was ofparticular importance to restore the original nailing system in

each of the damaged panels. A number of solutions were devised to

ensure that the original “pull,” or force of the nails, in each panel was

approximated as closely as possible. Most boards had little, if any, planar

distortion, or warping. Existing splits and gaps were not filled or otherwise

treated, since the panels were in equilibrium with the matrix sections, and

it was important to avoid introducing any new forces.

The most effective solution to restoring the original nailing sys-

tem in the damaged panels was also the simplest, as those nails where a

stub of about 1 cm had been left could be cut with a positive thread.

Solid brass extensions were then fabricated;^18 they were hollow on one

end, which was tapped with a negative thread to fit the threaded nail

stub. The other end ofthe brass extension was cut with a thread that

could be used to fasten it with a washer and nut to the back of the new

support (Figs. 5–8).

Treatment of the

Intarsia Panels

Condition of the

Intarsia Panels

486 Wilmering