The main purpose of this contribution is to report some first preliminary analyses of a new and never investigated decorative technique named Tattoo Wall, especially the possible changes due to ageing artificially induced by extreme humidity conditions in view of a possible application in crypts, churches or outside wall paintings. This innovative decorating technique involves transferring digital images on wall surfaces through a transfer paper with solvent-based ink and fixative. For the experimental tests, we chose to work on a color scale as wide as possible, to test each single color, and on different materials. The printed colors were applied on hydraulic mortar, containing marble powder combined with Ledan C30, particularly suitable for restoration in environments with high relative humidity (RH%). Moisture ageing was obtained by placing the sample in a box with RH% fixed to 92% thanks to the presence of salts (sodium sulphate deca-hydrated) for compressively two years (96 weeks). Reflectance spectrophotometry for color measurements and hyperspectral imaging (HSI) were used to assess the effect of high relative humidity exposure. The experimental data were statistically treated in order to evaluate their significance. Testing enabled us to verify the stability and durability of Tattoo Wall® under high relative humidity, with little chromatic alterations. Testing could and should be conducted also on different surfaces and materials (paintings on canvas and wood, oil on wall, etc.) to make it as complete as possible and guarantee the use of Tattoo Wall® in most cases of pictorial reintegration, reducing the risk of human error.
The focus of this study was to investigate the potential of hyperspectral imaging (HSI) in the monitoring of commercial consolidant products applied on wood samples. Poplar (Populus spp.) and walnut (Juglans Regia L.) were chosen for the consolidant application. Both traditional and innovative products were selected, based on acrylic, epoxy, and aliphatic compounds. Wood samples were stressed by freeze/thaw cycles in order to cause material degradation without the loss of wood components. Then the consolidant was applied under vacuum. The samples were finally artificially aged for 168 h in a solar box chamber. The samples were acquired in the short wave infrared (1000 to 2500 nm) range by SISUChema XL™ device (Specim, Finland) after 168 h of irradiation. As comparison, color measurement was also used as an economic, simple, and noninvasive technique to evaluate the deterioration and consolidation effects on wood. All data were then processed adopting a chemometric approach finalized to define correlation models, HSI based, between consolidating materials, wood species, and short-time aging effects.
The focus of this study was addressed to investigate the potentiality of HyperSpectralImaging (HSI) in the monitoring of commercial consolidant products applied on wood samples. Poplar (Populus Sp.) and walnut (Juglans Regia L.) were chosen for the consolidant application. Both traditional and innovative products were selected, based on acrylic, epoxy and aliphatic compounds. Wood samples were stresses by freeze/thaw cycles in order to cause material degradation. Then the consolidants were applied under vacuum. The samples were finally artificially aged for 168 hours in a solar box chamber. The samples were acquired in the SWIR (1000-2500 nm) range by SISUChema XL™ device (Specim, Finland) after 168 hours of irradiation. As comparison, color measurement was also used as economic, simple and noninvasive technique to evaluate the deterioration and consolidation effects on wood. All data were then processed adopting a chemometric approach finalized to define correlation models, HSI based, between consolidating materials, wood species and short time ageing effects.
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.
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