ity oscillations in the range of 10–15%. Essentially, the panel reacts more
or less as though it were unthinned.
Silica gel tiles were not added to the Francesco di Giorgio Martini
work; however, had the panel been more quickly reactive or had the envi-
ronmental conditions within the two institutions been less stable, they
would have been a likely option (and they remain an option in the future).
Whenever this type of secondary support is used, care should be
taken to secure the object in its frame by means of some kind offlexible
clip. Ifit were fixed rigidly and the panel were to increase its convex warp,
the necessary movement would otherwise be blocked by the frame rabbet.
Although the various phases oftreatment of these panels offer no
technical innovations, the project as a whole demonstrates the degree to
which overall context plays a determining role in assessing the appropri-
ateness of any proposed treatment. In this instance, solutions were repeat-
edly modified throughout the treatment process to accommodate new
physical and contextual information that came to light during the course
ofthe intervention (Fig. 33).T N F G M 357Figure 33
Metropolitan and Washington panels after
permanent rejoining.