ENVIRONMENTAL-RESEARCH FOR ART CONSERVATION (ERA)

The basic concept of this project is to identify and then use the chan ges which occur in the chemical and physical properties of traditional paint media both to indicate and integrate the effects of environment al conditions on paintings. To achieve this aim, test paint films are being prepared in accordance with traditional artists' recipes. Change s in material properties are monitored using a combination of non-inva sive spectroscopy (Bacci), microsensors, thermoanalytical techniques ( Odlyha), and microscale analytical mass spectrometry for molecular str ucture analysis (Boon). The test strips are calibrated by exposure to controlled environments (light, temperature, relative humidity and nox ious gases) and alterations in their properties are quantified. This p rovides information on the nature and rate of change at the molecular level and a data base for evaluating the molecular monitoring strips a fter their exposure in the field. Field sites have been selected and i nclude various locations in the Tate Gallery (UK), Sandham Chapel (Bur ghclere, UK), the Uffizi Gallery (It) and the Rijksmuseum (NL). Enviro nmental conditions of some of these locations are being evaluated at p resent using the glass sensors described in project EV5VCT92 0144. Sma ll piezoelectric quartz crystal humidity sensors will be installed to determine localised variations in relative humidity and temperature on [I] Stanley Spencer paintings in Sandham Chapel and [2] Giotto's ''Ma donna di Ognissanti'' in the Uffizi Gallery. In addition novel coating s using picture varnishes are being applied to similar piezoelectric q uartz crystal sensors to evaluate the effects of environmental impact on the chemistry of varnishes on paintings. Data are also being collec ted on the nature of chemical and physical changes in varnishes and pa int media in actual paintings at the molecular level.