Painting Materials Research Articles

Visualising varnish removal for conservation of paintings by fluorescence lifetime imaging (FLIM)

The removal of varnish from the surface is a key step in painting conservation. Varnish removal is traditionally monitored by examining the painting surface under ultraviolet illumination. We show here that by imaging the fluorescence lifetime instead, much better contrast, sensitivity, and specificity can be achieved. For this purpose, we developed a lightweight (4.8 kg) portable instrument for macroscopic fluorescence lifetime imaging (FLIM). It is based on a time-correlated single-photon avalanche diode (SPAD) camera to acquire the FLIM images and a pulsed 440 nm diode laser to excite the varnish fluorescence. A historical model painting was examined to demonstrate the capabilities of the system. We found that the FLIM images provided information on the distribution of the varnish on the painting surface with greater sensitivity, specificity, and contrast compared to the traditional ultraviolet illumination photography. The distribution of the varnish and other painting materials was assessed using FLIM during and after varnish removal with different solvent application methods. Monitoring of the varnish removal process between successive solvent applications by a swab revealed an evolving image contrast as a function of the cleaning progress. FLIM of dammar and mastic resin varnishes identified characteristic changes to their fluorescence lifetimes depending on their ageing conditions. Thus, FLIM has a potential to become a powerful and versatile tool to visualise varnish removal from paintings.Graphical

CURRENT STATE OF PROTECTIVE AND DECORATIVE PROPERTIES OF WATER-DISPERSION ACRYLIC COMPOSITIONS

The rapid progress of water-dispersion paints from the water-diluted group is due to a number of their advantages over other paint and varnishes from the category of environmentally friendly. The formulations of paintwork materials are dominated by aqueous dispersions of acrylic copolymers, acrylic styrole copolymers, homo- and copolymers of vinyl acetate. One of the main methods of targeted regulation of the properties of polymer composite materials and coatings is the use of surfactants (surfactants). As a result of adsorption phenomena, their physical interaction with the surface of dispersed particles and substrate, associations with film-forming molecules can significantly change the deformation-strength, insulating, adhesive, coloristic and other properties of paint coatings. The purpose of the work is a reasonable choice of polymer surfactants for obtaining water-dispersion acrylic coatings with a given set of properties. This determines the relevance of research. Objects. Film former - acrylic polymer, inorganic pigment - rutile-shaped titanium dioxide, modifying additives - polyestersiloxane copolymer (PES) and sodium polyacrylate (PAN), aqueous solvent. Conclusion. Analysis of the state and current trends in paint and varnish materials indicates the prospects of using water-dispersion acrylic compositions. The study of the physical and chemical regularities of processes involving surfactants, developed both in the volume of film-forming and at the interphase boundaries of its interface with pigment and air, is an important prerequisite for the formation of scientifically based approaches, when obtaining effective protective and decorative properties of coatings of water-dispersion compositions.

Traditional and modern pigments in Gino Severini's Swiss murals

AbstractBetween 1924 and 1947, Gino Severini decorated five churches in the Romand region of Switzerland with monumental religious wall paintings. This mural art played an important role in the Italian artist's career despite being mostly unknown and not easily found. The painting methods and materials of these modern Swiss murals were characterized by combining historical and archival research with onsite visual and scientific examination. Most pigments were identified with noninvasive methods integrating mapping techniques (i.e., technical photography and digital microscopy) with point analysis (x‐ray fluorescence and reflection FT‐IR spectroscopy). The results of these portable techniques were completed with SEM‐EDS, μFT‐IR FPA imaging, and μRaman analyses on micro‐samples which provided stratigraphic and compositional information to complement the noninvasive results. Overall, the data obtained show that Severini used both traditional pigments (e.g., Sangiovanni white and ochres/earths of various color) and modern ones, such as cadmium‐based pigments, with different painting techniques (e.g., zinc white was applied exclusively a secco). Apart from cerulean blue (cobalt stannate) and Naples yellow (lead antimonate) found only in two locations, the same set of pigments was documented in all of Severini's Swiss murals. The characterization of the artist's palette is important to understand the technical painting process followed by Severini, his interest on new painting materials available on the market and, at the same time, loyalty towards traditional painting methods, such as painting a fresco.

Reflectance Spectroscopy as a Novel Tool for Thickness Measurements of Paint Layers.

A major challenge in heritage science is the non-invasive cross-sectional analysis of paintings. When low-energy probes are used, the presence of opaque media can significantly hinder the penetration of incident radiation, as well as the collection of the backscattered signal. Currently, no technique is capable of uniquely and noninvasively measuring the micrometric thickness of heterogeneous materials, such as pictorial layers, for any painting material. The aim of this work was to explore the possibility of extracting stratigraphic information from reflectance spectra obtained by diffuse reflectance spectroscopy (DRS). We tested the proposed approach on single layers of ten pure acrylic paints. The chemical composition of each paint was first characterised by micro-Raman and laser-induced breakdown spectroscopies. The spectral behaviour was analysed by both Fibre Optics Reflectance Spectroscopy (FORS) and Vis-NIR multispectral reflectance imaging. We showed that there is a clear correlation between the spectral response of acrylic paint layers and their micrometric thickness, which was previously measured by Optical Coherence Tomography (OCT). Based on significant spectral features, exponential functions of reflectance vs. thickness were obtained for each paint, which can be used as calibration curves for thickness measurements. To the best of our knowledge, similar approaches for cross-sectional measurements of paint layers have never been tested.

Materials and Technique: The First Look at Saturnino Gatti

As part of the study project of the pictorial cycle, attributed to Saturnino Gatti, in the church of San Panfilo at Villagrande di Tornimparte (AQ), image analyses were performed in order to document the general conservation conditions of the surfaces, and to map the different painting materials to be subsequently examined using spectroscopic techniques. To acquire the images, radiation sources, ranging from ultraviolet to near infrared, were used; analyses of ultraviolet fluorescence (UVF), infrared reflectography (IRR), infrared false colors (IRFC), and optical microscopy in visible light (OM) were carried out on all the panels of the mural painting of the apsidal conch. The Hypercolorimetric Multispectral Imaging (HMI) technique was also applied in selected areas of two panels. Due to the accurate calibration system, this technique is able to obtain high-precision colorimetric and reflectance measurements, which can be repeated for proper surface monitoring. The integrated analysis of the different wavelengths’ images—in particular, the ones processed in false colors—made it possible to distinguish the portions affected by retouching or repainting and to recover the legibility of some figures that showed chromatic alterations of the original pictorial layers. The IR reflectography, in addition to highlighting the portions that lost materials and were subject to non-original interventions, emphasized the presence of the underdrawing, which was detected using the spolvero technique. UVF photography led to a preliminary mapping of the organic and inorganic materials that exhibited characteristic induced fluorescence, such as a binder in correspondence with the original azurite painting or the wide use of white zinc in the retouched areas. The collected data made it possible to form a better iconographic interpretation. Moreover, it also enabled us to accurately select the areas to be investigated using spectroscopic analyses, both in situ and on micro-samples, in order to deepen our knowledge of the techniques used by the artist to create the original painting, and to detect subsequent interventions.

Material and Imaging Analysis Procedure for the Investigation of Paintings in the Archbishop’s Palace of Seville

The Archbishop’s Palace of Seville harbours an important art collection with mostly works by great Renaissance and Baroque artists. However, the authorship of some paintings is unknown, and, in a few cases, there is an interest in discovering the painter due to the quality of the artwork. As a first step for this purpose, a systematic analysis procedure has been established using non-destructive techniques, such as UV photography and IR reflectography, to locate interventions and underpaintings, as well as X-ray fluorescence to identify original pigments and those of later interventions. The study following this established protocol is presented with the example of two paintings by unknown authors. They were made in different centuries representing, consequently, different styles. UV images showed several retouches, while IR reflectography revealed under-drawing and composition corrections (pentimenti). Furthermore, XRF identified the pigments applied in the production of the different colours and tonalities, allowing to characterise the artist’s palette, whose pigments generally agree with the dates when the artworks were produced. This study resulted in valuable information on painting materials and techniques, which will be useful in the search for authorships, among others.

Water depth effect on energy, exergy losses, and exergy efficiency of solar still with wick materials: an experimental research.

This study analyzes the energy and exergy destruction of a solar still with black painted wick materials (SS with BPWM) at different salt water depths (Wd) of 1, 2, and 3 cm. The coefficients of heat transfer for evaporative, convective, and radiant heat transfer have been calculated for a basin, water, and glass. The thermal efficiency and exergy losses caused by basin material, basin water, and glass material were also determined. An SS with BPWM at Wd of 1, 2, and 3 cm has produced a maximum yield of 0.4, 0.55, and 0.38 kg per hour, respectively. An SS with BPWM at Wd of 1, 2, and 3 cm has produced a daily yield of 1.95, 2.34, and 1.81 kg, respectively. From the SS with BPWM at Wd of 1, 2, and 3 cm, respectively, daily yields of 1.95, 2.34, and 1.81 kg were obtained. The highest exergy loss of the glass material, basin material, and basin water for the SS with BPWM at 1 cm Wd was 728.7, 133.4, and 123.8 W/m2, respectively. The SS with BPWM's thermal and exergy efficiency are 41.1 and 3.1% at 1 cm Wd, 43.3 and 3.9% at 2 cm Wd, and 38.2 and 2.9% at 3 cm Wd, respectively. The results show that compared to the exergy loss of basin water in SS with BPWM at 1 and 3 cm Wd, the basin water exergy loss of SS with BPWM at 2 cm Wd is minimal.

Reflecting the past, imag(in)ing the past: macro-reflection imaging of painting materials by fast MIR hyperspectral analysis

Imaging spectroscopy has been developed in the last two decades in the visible and infrared spectral range for detecting pigments and binders on paintings. The near-infrared (NIR) region has been proved effective for the discrimination of lipids and proteinaceous binders. More recently, the mid-infrared (MIR) range has also been tested on paintings. Reflection imaging prototypes already developed could be further optimized for cultural heritage analysis, for example by: enhancing the instrument configuration and performance; adopting compressive strategies to increase data processing speeds; using data validation to confirm that the processed image reflects the composition of a painted surface; and lowering price to enable more cost-effective analysis of large surface areas. Here, we demonstrate a novel hyperspectral Fourier transform spectrometer (HS FTS), which enables an imaging strategy that provides a significant improvement in acquisition rate compared to other state-of-the-art techniques. We demonstrate hyperspectral imaging across the 1400–700 cm−1 region in reflection mode with test samples and the painting ‘Uplands in Lorne’ (Acc. No.: GLAHA43427) by D.Y. Cameron (1865–1945). A post-processing analysis of the resulting hyperspectral images, after validation of reference samples by conventional Fourier transform infrared spectroscopy, shows the potential of the method for efficient non-destructive classification of different materials found on painted cultural heritage. This research demonstrates that the HS FTS is a convenient and compact tool for non-invasive analysis of painted cultural heritage objects at spatio-spectral acquisition rates potentially higher than current FTS imaging techniques. Ultimately, when combined with fast graphics processing unit-based reconstruction, the HS FTS may enable fast, large area imaging.Graphical abstract

MODERN METHODS OF APPLYING PAINT AND VARNISH COATING

The article refers to the application of paint coatings on the base, that is, metal. On the surface of metal structures or metal products, a thin layer of paint and varnish material is applied, which allows you to protect the substrate from harmful environmental factors.There are several ways to apply protective coatings the article talked about the advantages and disadvantages of each of them. in the course of the analysis, the method of applying the paint coating by spraying was chosen. This method allows you to save paint and varnish material, controlthe thickness of the applied layer and use the necessary amount of materials to obtain reliable protection of the metal. The article also provides an analysis of the spray guns that are used today.A method was proposed to change the design of the spray gun for applying materials of different consistency such as primer varnish paint etc.

Development and research of syntactic foams for antenna devices parts manufacture

Foam plastics are always widely used in antenna-feeder systems due to the low values of the dielectric constant ε and the tangent of the dielectric loss angle tgδ. Structural elements of such antennas are usually made by gluing blanks cut from expanded polystyrene plates or from filling polyurethane foam. However, these methods turned out to be low-tech due to the high labor intensity of the process, the inhomogeneity of the dielectric properties of structures and the unsatisfactory quality of the painted surface due to the low chemical resistance of these materials to solvents of paint and varnish materials. Syntactic foams, which are a special type of gas-filled polymers, in which hollow spherical filler particles are distributed, in comparison with traditional foams, have increased mechanical strength, electrical strength, resistance to climatic factors, less density difference and better surface quality. It is the advantages of syntactic foams listed above that make them relevant materials in the manufacture of structural elements of antennas. The purpose of the work is to study the possibility of obtaining products from low-density syntactic foam by combining an expandable polymer matrix with a filler in the form of hollow glass microspheres. The limits of filling the polymer matrix by the filler have been established. The material dielectric characteristics (dielectric constant ε and the tangent of the dielectric loss angle tgδ) and strength (compression stress at 10% deformation) characteristics have been investigated. The resistance of the material to the influence of climatic factors has been investigated. The technology of manufacturing the product by the flooding method has been developed. Also the effect of paint and varnish coatings on surface quality and dielectric characteristics of foams of low density has been investigated. The obtained results can be used to create structural elements of antennas.

Upgrading the performance of a solar air collector with flexible aluminum air ducts and graphene nanoplatelet-enhanced absorber coating

Solar air collectors (SAC) have had great importance nowadays as far as clean energy production is concerned. In this study, the novel double flow solar air collectors were designed and their performance was investigated. This study aims to illustrate how affect the thermal performance and sustainability indicators of a newly-designed solar air heater with nano-enhanced aluminum air ducts instead of conventional sheet metal absorber plate. Two double flow solar air collectors, the former of which includes flexible aluminum air ducts coated by black matte paint (DSAC/FAD), whereas the latter one includes sheet metal plate coated by black matte paint (DSAC) were studied under the same environmental conditions. Moreover, the effect of nanoparticles on performance was investigated by adding nanoparticles into the paint. For this purpose, a set of experiments were simultaneously performed utilizing solar air collector with flexible aluminum air ducts coated with black matte paint (DSAC/FAD) and the double flow solar air collector with flexible aluminum air ducts coated with graphene nanoplatelet-included black matte paint (DSAC/NFAD). The experiments were conducted with the same fans of 40 W power. The energy, exergy and such sustainability indicators as waste exergy ratio (WER) and sustainability index (SI) were examined for each design. In the second part of experiments, the maximum thermal efficiency was obtained as 73.94% for the (DSAC/NFAD). The COP values for DSAC (Day 1), DSAC/FAD (Day 1), DSAC/FAD (Day 2), and DSAC/NFAD (Day 2) were found as 4.82, 4.52, 4.56, and 5.22, respectively. Similarly, the mean exergy efficiency of the (DSAC/NFAD) was calculated as 37.73%, whilst DSAC had the mean exergy rate of 17.93%. For the sustainability indicators, the best results of WER and SI were achieved in the experiments conducted on DSAC/NFAD. It was concluded that the double flow solar air collector with flexible aluminum air ducts can be utilized for thermal performance enhancement. Moreover, it is predicted that the outcomes of this study enlightened the new research topics to be emerged.

Preserving the Ephemeral: A Micro-Invasive Study on a Set of Polyurethane Scenic Objects from the 1960s and 1970s.

Among the innovative materials used by 20th-century artists, polyurethane (PUR) has been shown to be highly unstable, and therefore artworks made of it are now in need of careful conservation strategies. This study presents a multi-analytical investigation of PUR foam scenic objects originally made between the 1960s and 1970s during the Italian Arte Viva movement. The main components in the foam and additives were characterized through micro attenuated total reflectance infrared spectroscopy (μ-ATR-FTIR) and pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). Painted samples were further investigated through μ-FTIR and Raman spectroscopy to define binders and pigments. The use of μ-ATR-FTIR in combination with evolved gas analysis-mass spectrometry (EGA-MS) allowed the variable conditions of the artworks to be assessed and attained some insights into the chemical processes responsible for aging. At the same time, morphological changes due to the degradation phenomena were recorded through optical (OM) and scanning electron microscopy (SEM). The detailed characterization of the PUR foam and painting materials was helpful in attaining some insights into harmful environmental parameters for the artworks, thus informing preventive conservation.

AUTOMATION OF THE PROCESS OF BITUMEN PRODUCTION

One of the most important directions in the field of oil refining is the rational use of oil residues by involving them in processes such as visbreaking, coking, de-asphalting, bitumen production. Petroleum bitumen is used in road construction, in the repair of roads, airfields, in industrial and civil construction (for the manufacture of roofing materials, for the insulation of pipelines from ground corrosion, for the preparation of paint and varnish materials). The quality of petroleum bitumen is a determining factor in ensuring the durability of road surfaces. To date, up to 70% of bitumen produced in Kazakhstan and the CIS countries do not meet the assortment and quality requirements of the modern market, and this primarily concerns bitumen for road, construction and special purposes. The decrease in natural oil reserves and the difficulty of obtaining high-quality bitumen from processed raw materials at most bitumen plants necessitates the search for new materials to obtain binders of a given quality. The process of bitumen production, carried out on an industrial scale, is very complex, but by now it has been sufficiently studied. However, the approach to the study of this process from the standpoint of the physico-chemical technology of oil dispersed systems reveals new aspects that allow us to hope for its further intensification. Due to the increasing volumes of consumption and the expansion of the field of application of petroleum bitumen, the issue of searching for new raw materials is acute. One of the most promising deposits of petroleum bitumen rocks are West Kazakhstan, where more than 50 deposits with reserves of 152 million tons have been discovered. However, to date, the extraction of petroleum bitumen rocks and their use in construction have not acquired significant proportions, due to their insufficient knowledge and imperfection of their processing technology. Until now, the main attention in matters of oxidation is paid to the study of the state of the vapor–liquid system, calculations of the partial pressure of volatile components of the oil system depending on its composition and external conditions, which is fundamental for technological calculations. In this case, oil is represented as a multicomponent molecular solution, the vapor-liquid interface is considered flat, and the vapor pressure above the flat surface is equal to the pressure in the liquid phase. In addition, in all thermodynamic and technological calculations, the vapor-liquid system is thermodynamically formed, leaving the process of vapor phase generation without due attention.

Laser-based techniques for the non-invasive characterisation of grisaille paints on stained-glass windows

Grisaille was the first paint applied on stained-glass panels, used in Europe since the twelfth century. Historical written sources described the use of iron and copper together with a high lead-silica base glass in the grisailles production. This project aims to study the evolution of the grisaille paint composition throughout time and the changes in the raw materials used in their production using non-destructive and non-invasive techniques. To achieve this objective, 23 grisaille samples dated from the 13th to the twentieth centuries from nine different countries (Portugal, Poland, United Kingdom, Sweden, Norway, Belgium, Low Countries, Germany, and France) were studied by means of micro particle-induced X-ray emission (μ-PIXE), micro energy dispersive X-ray fluorescence (μ-EDXRF), laser-induced breakdown spectroscopy (LIBS), laser-induced fluorescence (LIF), non-linear optical microscopy (NLOM) in the modality of multiphoton excitation fluorescence (MPEF) and optical microscopy (OM). The results showed that it was possible to identify compositional differences and patterns throughout the samples when compared with literature results. The preference for using copper in central and south-central European countries and the addition of new compounds (CoO, Cr2O3, MnO) as colouring agents since the nineteenth century was verified. The LIBS analyses allow the identification of boron on two samples, confirming the change of base glass components since the seventeenth century. The NLOM-MPEF showed the capability of this technique to measure the grisaille paint layers’ thickness. This non-invasive multi-analytical and complementary approach proves itself efficient in identifying changes in the grisaille’s composition throughout time, which can be interpreted as changes in the raw materials and manufacture used in the production of these paint materials.

Acquisition strategies for in-situ hyperspectral imaging of stained-glass windows: case studies from the Swiss National Museum

Over the last decade, hyperspectral imaging has become a popular technique for the non-invasive identification and mapping of painting materials in many typologies of artworks, thanks to the possibility of obtaining spectral information over the spatial region. A few attempts have also been made on stained-glass windows to identify the chromophore elements responsible for glass color. Hyperspectral imaging of stained glass can be complex; in most cases, stained-glass windows are an integral part of buildings, and sunlight represents the natural light source for illuminating these artifacts. While it may be considered an advantage, sunlight is not homogeneous throughout the day, and different weather conditions can affect the quality of the hyperspectral images. In addition, the presence of buildings and vegetation in the background could also modify the colors of the stained-glass windows and consequently alter the characteristic peaks of the chromophores in the spectra. This work aims to solve some of these issues and proposes different strategies to improve the results obtainable in situ. The methodology was tested on stained-glass panels displayed in the windows of the Swiss National Museum. Stained-glass panels located in windows of an internal wall were also analyzed, developing a lighting setup to account for the lack of natural light. Hyperspectral images of the selected stained glass were acquired multiple times, choosing different transmittance references for the preprocessing and exposure time to evaluate differences in the collected spectral images. The use of a diffuser sheet to mitigate the effect of external factors was also tested on some panels exposed to sunlight. Results from representative case studies will be presented to discuss the feasibility and limitations of in-situ hyperspectral imaging applications on stained glass and provide some general recommendations to consider during the acquisitions.

Liquid Foam-Ethyl Vinyl Acetate Adhesive Systems for Lining Process of Paintings: Prospects of a User-Friendly, Harmless Alternative to Conventional Products

The lining of paintings is a process of conservation science and art restoration used to strengthen, flatten, or consolidate paintings on canvas by attaching by means of adhesives a second canvas to the back of the existing one. To this aim, the prospects of the use of ethyl vinyl acetate (EVA) resins in aqueous dispersion applied as an adhesive in a foam form have been investigated in the present study. The key physical properties of the foam have been investigated, with a deep focus on rheological behavior and the drying rate, comparing the results with those obtained using the liquid products that are commercially available. Dedicated mock-ups have been prepared to test the adhesive for the lining process, inspecting adhesion strength, colorimetric properties, and the influence on the possible chromatic and visual alteration of the surface, also looking at the chemical interaction with painting materials and the deterioration after an artificial ageing process. The results obtained clearly indicated that the proposed technology is very suitable for the targeted application, and an EVA water-based foamed dispersion can be used for paintings' lining, in view of the ease of application, being an appropriate adhesion, no chemical interaction, nor the deterioration of the painting.

The Use of TRI-Funori® as a Binding Medium for Chromatic Reintegration in Contemporary Unvarnished Paintings

Each material is suited to the different paint material characteristics and pictorial techniques of various artworks by contributing to the pictorial surface’s stability and visual unity, and the ability to display it without interruption. For this article, the polysaccharide TRI-Funori was tested and used as a binding medium for chromatic reintegration in three oil and acrylic mockups of the artwork by Portuguese artist Jorge Martins. This choice was based on characteristics such as compatibility, low toxicity, water-based properties, and good visual properties for color matching. Advantages such as transparency and less tendency to yellow, capacity to dry matte, and ease of removal were observed. It presents good dispersion of inorganic pigments, good visual properties, and good adhesion to oil and acrylic surfaces with or without preparation. However, it also presents disadvantages such as weak dispersion of organic pigments, for example [PB15] Phthalocyanine Blue or [PR83] Carmine Rose, and the tendency to become powdery. During the drying process, it tends to lighten, making the color adjustment process difficult. The mimetic method, achieved with small dots, was used for retouching. The medium was applied with Ferrario® pigmenti puri and Winsor & Newton® powdered pigments, and chromatic reintegration was carried out with a fine brush Winsor & Newton® Finest Sable no1.

Investigation of the neutron radiation protective properties of chlorophyll and carotenoid

In this study, we have investigated neutron radiation absorption properties of chlorophyll and carotenoid. Our aim is to show that chlorophyll and carotenoid, which are naturally found in every green plant, can be used to make a cream, medicine, paint, or shield material against neutrons. Neutron radiation is generally used in many applications such as diffraction and scattering experiments, material crystallography, diagnosis and therapy in medicine, cell DNA studies in biology, condensed matter physics, materials research and development, solid-state chemistry, mineralogy, geology, and the study and improvement of the structural properties of materials. In order to reduce or completely eliminate the damages that can be caused by direct or scattered neutrons by the people working in these studies or other people in the environment, materials with high shielding are needed to absorb neutrons. In order to understand that chlorophyll and carotenoid can be used in the production of neutron shielding materials, the neutron radiation absorption parameters of these materials were investigated. The parameters, which are widely used in neutron shielding studies such as an effective removal cross section, half value layer, mean free path, and neutron transmission factor (NTF) were estimated using the Monte Carlo simulation GEANT4 code for both fast and epithermal neutrons. In addition, the dose rates of all samples were determined by using an 241Am–Be fast neutron source. All theoretical and experimental results obtained to understand the absorption capacities of chlorophyll and carotenoid were compared with paraffin, which is widely used in neutron shielding applications.It is to be noted that determined that chlorophyll showed an effective shielding against fast neutrons and carotenoid showed an effective shielding against epithermal neutrons. Investigation revealed that these materials are alternate shielding materials against neutron radiation for the production of medicine, composite material, and paint to be developed for neutron radiation.

Beauty Revealed: Technical Analysis and Treatment of Zand and Qajar Oil Paintings

ABSTRACT The interiors of Zand and Qajar palaces were often decorated with idealized portraits meant to convey wealth and internationality through depiction of European goods, jewelry, and other social signifiers. Five figurative oil paintings dating from the late 1700s to early 1800s were analyzed non-destructively using x-radiography, infrared reflectography, and macro-area x-ray fluorescence spectroscopy. Selective microscopic sampling enabled pigment and binder identification using Raman and Fourier transform infrared spectroscopy and scanning electron microscopy coupled with energy dispersive x-ray spectroscopy. All paintings are oil on cotton canvas and utilize a limited palette that includes Prussian blue, orpiment, and vermillion. Four paintings contain copper alloy leaf used to simulate gold jewelry and textiles. Artisanship expertise varies and European influences, including perspective and shading, are unevenly incorporated; workshop involvement is suggested by differing qualities of rendering within a given work. One painting, Dancing Girl (1192 AH/1778 CE) by Muhammad Baqir, was fully treated to remove thick layers of discolored shellac varnish and overpaint that distorted the appearance of the work. This study provides insights into the painting materials and techniques of the late Zand and early Qajar period, and practical methodologies for their treatment and continued preservation.

Scientific Investigation of Contemporary Pastel Painting by Roberto Sebastian Matta: Characterization of Original Materials through Multispectral Imaging and Spectroscopic Techniques

The conservation of contemporary art often offers unique occasions to study complex multi-material artworks and understand their creative process and esteem degradation distress. The recent diagnostic campaign on the surrealist artwork Perché le vittime vincano (For the victims to win) (1974–75) by the artist Roberto Sebastian Matta allowed us to characterize the original painting materials (pastels on spolvero paper), never investigated and completely unknown, in order to support the imminent restoration. Due to the great dimensions of the artwork and its conservative issues, non-invasive multispectral imaging (HMI) analyses were done to investigate the whole painted surface, mapping and differentiating original materials and possible degradation patterns. Imaging data supported analytical characterization analyses run through elemental (portable X-ray fluorescence spectroscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy) and molecular spectroscopy (Fourier transform infrared and portable µ-Raman spectroscopy) to identify the original artist’s materials and to support the restoration operations. The analysis revealed that the painting materials used by Matta are pastels characterized by modern pigments and dyes, such as Cu-phthalocyanines, chrome orange, titanium and zinc whites, compacted with kaolin without any organic binder or with a possible minuscule amount of gum.