AIC's 42nd Annual Meeting

In the debate about safe climate ranges, the majority of scientific literature concerning the reactivity of wooden objects which supports the new proposed guidelines has been carried out in laboratory conditions, assuming that the characteristics of the sample can be safely extrapolated to real size objects. Some field measurement campaigns have been carried out in an attempt to detect the most irreversible damage element, the crack, although there is probably more to investigate regarding the long term warping of real objects under fluctuations. This paper will focus on the latter aspect.
Case studies monitoring long-term warping of panel paintings have been conducted for many years. The mechanical monitoring has been combined with microclimatic logging, in order to provide quantitative information directly related to the environmental conditions; these data are useful to validate mathematical models that eventually may predict the long-term behaviour of objects.
The climate fluctuations can have both temporary and permanent effects on hygroscopic objects and they are a potential cause of damage.
Although there is long-term evidence of the generally positive effects of a microclimate within the standard range of allowable fluctuations, we lack wide experimental data regarding the effects of broader ranges on real objects over a long period of time.
Panel paintings are useful in representing the complexity of possible reactions.
Due to the specificity of each artwork, both from its structural point of view and from its previous microclimatic history (for the most part totally unknown), the analysis of an artifact’s response to short- and long-term variations can supply useful information about its “individual” sensitivity to the exhibition microclimate, suggesting the adoption of more or less rigid parameters.
The benefits of such an approach are many, both from the preventive conservation point of view and as a support for conservation interventions. The methodology can be useful in monitoring objects in transit and to evaluate the effects of structural interventions.
Due to the size of the instruments employed, the methodology is minimally invasive. Since it is placed on the back of the support, the device can also be used while the object remains on exhibition without disturbing visitors and, thanks to recent improvements, it can be easily detached and exactly repositioned without affecting the quality of measurement.
From the scientific point of view, widening the data-base of monitoring experiences would benefit  the understanding of this sensitive issue in the conservation of panel paintings.