The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to artificial irradiation in a Solar Box. Colour changes were monitored with a reflectance spectrophotometer. Surface chemical modifications were evaluated by measuring the infrared spectra. Hyperspectral imaging was also applied to study the surface wood changes in the visible-near infrared and the short wave infrared wavelength ranges. The data obtained from the different techniques were compared to find the possible correlations in order to evaluate the applicability of the Hyperspectral imaging to investigate wood modifications in a non-invasive modality. The study of colour changes showed an important variation due to photo-irradiation which is the greatest change occurring within the first 24 hours. Infrared spectroscopy revealed that lignin degrades mainly in the first 48 hours. Concerning Hyperspectral imaging, the spectral features in the visible-near infrared range are mainly linked to the spectral shape, whereas in the short wave infrared cellulose and lignin affect shape and reflectance levels. The proposed approach showed that a correlation can be established between colour variation and wood degradation in the visible-near infrared range; furthermore in the short wave infrared region surface chemical changes can be assessed.

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The aim of this study is to investigate the yellow pigments based on lead, tin, and antimony produced according to the ancient treatises, recipe books, and literary sources. The pigments considered in this study are lead/tin yellow type I (Pb2SnO4), lead/tin yellow type II (PbSn1−xSixO3), lead antimonate or Naples yellow (Pb2Sb2O7), and lead/tin/antimony yellow (Pb2SnSbO6,5). Color was measured by X‐Rite reflectance spectrophotometer to investigate the chromatic characteristics of the produced pigments in relation to the recipes. The pigments were chemically characterized by scanning electron microscopy with energy‐dispersive spectroscopy, and micro‐Raman analysis to investigate the influence of reagents, temperature, and melting modalities in the compositions of the produced powders. A part of the study was devoted to the study on the use of these yellow pigments in the art history especially concerning the modus pingendi of Italian artists between 14th and 18th century. The results of this study highlighted the possibility to obtain pigments with different colors and compositions according to the reagents, to the temperature, to the melting modality, in particular if single or double firing was used. © 2016 Wiley Periodicals, Inc. Col Res Appl, 41, 226–231, 2016

The aim of this work is to study the surface modifications of poplar (Populus spp.) wood by reflectance spectrophotometry and Fourier Transform Infrared (FT-IR) spectroscopy in order to understand the mechanisms that cause the changes and to suggest possible solutions to avoid the degradation phenomena. Since colour changes on wood surfaces are due to photo degradation of its chemical constituents, the study of the relationship between CIELAB colour changes and changes in chemical composition due to irradiation is of practical importance both in cultural heritage and in contemporary artefacts and objects.Concerning the surface protection of wood, starting from the results obtained by testing different commercial products, the attention has been focused on Linfoil®, a novel organic preservative/consolidant product that seems to attract a great interest in the field of conservation of wooden artefacts. Linfoil® was chosen and analysed in order to understand its composition and its time stability using reflectance spectrophotometry, FT-IR spectroscopy and analytical pyrolysis coupled to a gas chromatographic-mass spectrometric system.Colour monitoring allowed to find that wood surface colour undergoes an important variation due to photo-irradiation, occurring within the first 24 hours and mainly due to L* decrease and b* increase. Though Linfoil® treatment modifies wood colour, nevertheless it seems to protect wood surface by reducing the yellowish. FT-IR spectroscopy allowed to investigate the rate of photo-degradation of wood surface due to lignin oxidation. The most important result is that a correlation of the colour changes may be derived with the photo-degradation of lignin obtained by FT-IR analysis.