Washington panel was motivated primarily by the need to find a solution
that would physically protect the tips of the fragments without falsifying
the aesthetic of the object. Now that the panels were permanently
rejoined, it made sense to add the missing strips to the sides of the
Metropolitan panel as well, in order to simplify the perimeter, reflect the
original fabrication method, and strengthen the entire construction.
It was decided not to continue the addition across the bottom
edge of the picture because it was considered unnecessary. Not only would
the end-grain attachment present its own problems, it would not in itself
resolve any other problem.
The back surface of the Metropolitan portion of the panel had
been scraped in order to remove all wax and glue residues, and it was now
judged to be potentially highly reactive to humidity fluctuations. A coat
ofAcryloid B72 was applied; this product is not totally impermeable but
merely slows down the moisture exchange rates.
Two crosspieces similar to those already applied to the Washington
portion were fabricated and attached (Fig. 30). The coat of Acryloid B72
applied as a moisture barrier would also facilitate the release of the retain-
ing pegs of the crosspiece system in the event that too much stress were to
accumulate at some point in the future.
The two institutions formally agreed to alternate custody of the
newly rejoined panel every five years (beginning in Washington, since it
had first been exhibited briefly at the Metropolitan for the exhibition of
Sienese Renaissance painting). The interval was considered reasonable
given the proximity of the two museums. A custom-designed crate
equipped with cushioning for shock as well as vibration absorption and
thermal insulation was then provided. Whenever the painting travels, it
will be accompanied by museum couriers and transported via truck with
air-ride suspension and climate control, for better control of cargo han-
dling and climatic variables than if the painting were transported by air.
One final alteration was made to the secondary support upon its
return to New York in October 1994. Although the four Florentine-typeT N F G M 355Figure 28
Gluing of the blocks.
Figure 29, right
Upper right portion ofthe joined panels.
Figure 30, far right
Rev erse ofthe joined panels after application
ofthe crosspieces on the Metropolitan panel.
Note the strips newly added to the sides of
the panel, as well as the continuous narrow
strip of poplar that forms a bridge to the
Washington portion, greatly increasing the
stability of the joint.