The Art of Everyday Objects: A Non-Invasive In Situ Investigation of Materials and Techniques of Italian Pop Art Paintings on Aluminium

Two paintings, made on aluminium support by Silvio Pasotti (among the major exponents of 1960s Italian pop art) were investigated in a totally non-invasive manner to identify the materials used by the artist. Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), visible reflectance spectroscopy, and spectrofluorimetry with visible excitation were exploited as molecular analysis techniques, which are particularly suitable to recognise also synthetic organic materials, such as pigments and binders. The effectiveness of this multi-analytical approach was demonstrated, leading to the identification of several synthetic organic pigments, both conventional and “special effect” ones, introduced during the first half of the 20th century, as well as some well-established inorganic ones. Combining FTIR results both in the medium and near IR ranges, considerations regarding the binders employed by the artist could also be made, suggesting the use of both nitrocellulose and acrylic paints. Imaging techniques, such as IR reflectography, false colour IR, UV induced fluorescence, and portable microscopy, were also used to achieve a better knowledge of the painting practice.

Portable, non-destructive colorimetry and visible reflectance spectroscopy can accurately identify heat-treated South African silcrete

The objective of this study was to determine if visible reflectance spectroscopy and quantitative colorimetry represent viable approaches to classifying the heat treatment state of silcrete. Silcrete is a soil duricrust that has been used as toolstone since at least the Middle Stone Age. The ancient practice of heat treating silcrete prior to knapping is of considerable interest to paleolithic archaeologists because of its implications for early modern human complex cognition generally and the ability to manipulate the material properties of stone specifically. Here, we demonstrate that our quantitative, non-invasive, and portable approach to measuring color, used in conjunction with k-Nearest Neighbors “lazy” machine learning, is a highly promising method for heat treatment detection. Traditional, expert human analyst approaches typically rely upon subjective assessments of color and lustre and comparison to experimental reference collections. This strongly visual method can prove quite accurate, if difficult to reproduce between different analysts. It is thus surprising that until now, no published study has sought to exploit an instrumental approach to measuring color for classifying heat treatment state in silcrete. In this work, we measured percent reflectance for the visible spectrum (1018 variables) and tristimulus color values (CIEL*a*b*) in unheated and experimentally heat treated silcrete specimens from three sources in South Africa. k-NN classification proved highly effective with both the spectroscopy and colorimetry data sets. An important innovation was using the heat treatment state predicted by the k-NN model for the majority of replicate observations of a single specimen to predict the heat treatment state for the specimen overall. When this majority voting approach was applied to the 746 individual observations in this study, associated with 94 discrete silcrete flakes, both spectroscopy and colorimetry k-NN models yielded 0% test set misclassification rates at the specimen level.

The combined use of SEM-EDX, Raman, ATR-FTIR and visible reflectance techniques for the characterisation of Roman wall painting pigments from Monte d’Oro area (Rome): an insight into red, yellow and pink shades

The aim of this work has been the identification of the painter’s materials employed in the wall decoration of some destroyed buildings dating approximately between the first century B.C. and the first century A.D. This research originates from a previously started joined archaeological and analytical investigation concerning a varied group of findings that resulted from a rescue excavation performed by Soprintendenza Archeologica in the area of Monte d’Oro in Rome. The focus of this study progression has been directed to a numerous selection of monochrome red, pink and yellow-pigmented fragments. The analyses were performed by means of scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) combined with Raman and Fourier transform infrared (FTIR) spectroscopies; visible reflectance measurements have also been carried out and the relevance of this technique in such a kind of archaeological studies has been highlighted. Most attention has been given to the assessment of the performances of non-destructive techniques achieved by portable Raman, and visible reflectance instrumentation to test their diagnostic capabilities. In addition to the expected and well-known pigments such as cinnabar, red ochre, hematite for the reds and yellow ochre for the yellows, the study highlighted a diffuse use of mixed colours and in some cases the possible presence of overlapped painted layers and confirmed the presence of gildings. Among the mixtures of pigments, the most singular outcome concerns the pink fragments revealing the possible application of bone white, which seems to be rather uncommon as a pigment in Roman wall decorations.

The Combined Use of SEM-EDX, Raman, ATR-FTIR and Visible Reflectance Techniques for the Characterisation of Roman Wall Painting Fragments From Monte D’Oro Area (Rome): An Insight onto Red, Yellow and Pink Shades.

The aim of this work has been the identification of the painter’s materials employed in the wall’s decoration of some destroyed building dating approximately between the first century B.C. and the first century A.D. This research originates from a previously started joined archaeological and analytical investigation concerning a really varied group of findings that resulted from an excavation performed by Soprintendenza Archeologica in the area of Monte d'Oro in Rome. The focus of this study progression has been directed to a numerous selection of monochrome red, pink, and yellow pigmented fragments. The analyses were performed by means of scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) combined to Raman and Fourier transform infrared (FTIR) spectroscopies; visible reflectance measurements have also been carried out in order to evaluate its appliance in such a kind of archaeological studies. Most attention has been given to the assessment of the performances of non-destructive techniques, precisely the ones achieved by portable Raman and visible reflectance instrumentation, above all to test their diagnostic capabilities. In addition to the expected and well-known pigments such as cinnabar, red ochre, hematite for the reds and yellow ochre for the yellows, the study highlighted a diffuse use of mixed colours and/or overlapped painted layers and confirmed in some cases the presence of gildings. Among the mixtures of pigments, the most singular outcome concerns the pink fragment revealing the possible application of bone white, which, based on of the known literature, seems to be rather uncommon as pigment in Roman wall decorations.

Manuscript Illumination in 19th-century Italy. Material Analysis of Two Partial Copies from the Squarcialupi Codex

The illuminations in two Italian manuscripts are still a mystery today. Both manuscripts were based fully or partly on the Florentine Squarcialupi Codex (Florence, Biblioteca Medicea Laurenziana, Med. Pal. 87) dating from around 1410/15. With the help of a multi-analytical, non-destructive approach employing mobile instrumentation (XRF spectroscopy, visible reflectance spectroscopy and infrared reflectography), we examined the manuscripts Toronto, Thomas Fisher Rare Book Library, MSS 09700 and Düsseldorf, Kunstpalast, Inv. K 1925-67 for the first time with regard to their production processes. The identification of modern pigments allows them to be contextualized in illumination practices of the 19th century. Manuals of that time provide a wealth of information on specific illumination practices and the availability of writing and painting materials, which correlates with the actual artefacts.

Ga-Doped ZnO Nanostructured Powder for Cool-Nanopigment in Environment Applications

Gallium (Ga) doped zinc oxide (ZnO) nanocrystals were successfully synthesized via a γ-radiation-assisted polymer-pyrolysis route. Ga doped ZnO samples with Ga and ZnO precursor salts with molar ratios of 0%, 3%, 5%, and 10% were produced. A γ-radiation dosage of 1.5 kGy was used for polymerization initiation during the sample preparation. The properties of the obtained nanocrystal samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible absorption, NIR-VIS-UV diffused reflectance, and high-resolution transmission electron microscopy (HR-TEM) characterization techniques. XRD results revealed the formation of ZnO nanocrystals with wurtzite structure for both Ga-doped and undoped ZnO samples. Noticeable increasing in the line broadening of the XRD peaks as well as pronounced decreasing of crystallite size were observed with the increasing Ga ratio in the samples. Optical peaks around Ga:ZnO samples showed a blueshift in the optical absorption peaks with increasing Ga content. These results are in good agreement with the dependency of crystallites size as well as grain size on Ga ratio obtained from XRD and TEM images, which make them fit well for the powder cool-pigment applications. The doped samples showed high values of NIR reflectance (RNIR*) with percentage varied from 84.25% to 89.05% that enabled them to qualify for cool-nanopigment applications. Furthermore, such doped samples registered low values of visible reflectance (RVIS*) that enabled to reduce the glare from the reflected visible sunlight.