Azurite mineral is usually found in association with malachite (Cu 2CO 3(OH) 2), the green basic carbonate of copper, and often with other copper-rich minerals (e.g. The mineral azurite is found in many parts of the world in the upper oxidized portions of copper ore deposits. However, the spectra obtained from three manuscripts suggested a certain influence of the parchment support, which indicates thinner paint layers.Īzurite (Cu 3(CO 3) 2(OH) 2), is composed of basic copper carbonate. Only an insignificant influence of the support on the spectra from the mock-ups was observed. The results showed that the binding medium content in the mock-ups usually was too low for a reliable determination by rFTIR (except the ones with the highest contents), whereas it was possible to characterize the varnish materials. Furthermore, mock-ups on aluminium foil were prepared to evaluate the influence of the support on the reflection spectra. Additionally, some of the specimen were varnished using the binders mentioned above.
In order to assess the possibilities and to distinguish between proteinaceous and carbohydrate binders, mock-ups with azurite were prepared on parchment support with various quantities of binders. Moreover, both were used in many cases also as “varnishes” in order to improve optical and mechanical properties of the paint layer. According to the literature, mainly glair (egg white) and plant gums were applied as binding media for azurite. 8 in the collection of the Austrian National Library), as well as the earliest known map of Vienna (Albertinischer Plan from 1421, Wien Museum) showed. However, the characterization of the used binding media is rather difficult, as the analysis of four medieval manuscripts from the late thirteenth to the fifteenth century (e.g. In illuminated manuscripts, a reliable identification of oxyanion pigments such as azurite by rFTIR is simple, as several combination and overtone bands are strongly enhanced compared to transmission mode.
0 kommentar(er)
