The microlimate control for a museum showcase: the case of a painting on a wooden board in S.Giusto Chuch (Trieste – Italy)

After the restoration, the thirteenth-century panel painting representing Christ and some saints conserved in the S. Giusto Cathedral of Trieste (Italy) posed the classic problem of balancing on one hand the preservation of the cultural heritage, the other the enjoyment by the public. Not always these two requirements are easily consistent. Appropriate environmental conditions are the main guarantee for the preservation, conversely an aggressive microclimate can become the main cause to a rapid degradation and visitors can help themselves as potential vehicles of pollutants and dust. Given the type of wood used as support material to the painting extremely sensitive to variation of the air temperature and air humidity conditions, it is immediately apparent the need for careful control of environmental and air quality parameters. The conservation managers, in cooperation with the authors, choose to place the painting in a showcase equipped with climate control system. In order to minimize maintenance and operating expenses, the control of the relative humidity has been performed using hygroscopic materials leaving the air temperature swing; this parameter however, was mitigated by the presence of the massive structure of the S. Giusto Cathedral.