Fiber Optic Reflectance Spectroscopy Research Articles

Changes in the production materials of Burmese textiles in the nineteenth century—dyes, mordants and fibres of Karen garments from the British Museum’s collection

The materials of six Karen textiles from the British Museum’s collection were investigated with the main aim of studying the production changes over the course of the nineteenth century and how these changes related to local and colonial trade networks. The textiles span chronologically from the 1830s to the early 1900s according to their attribution dates, and include traditional garments such as tunics and skirts, in addition to representing a broad colour palette and different dyeing and weaving techniques. The investigation was conducted non-invasively by using digital microscopy, broadband multispectral imaging (MSI) and fibre optic reflectance spectroscopy (FORS). The results guided a sampling campaign during which samples were taken and investigated by optical microscopy (OM), scanning electron microscopy energy dispersive X-ray spectrometry (SEM–EDX) and high-performance liquid chromatography coupled to diode array detector and tandem mass spectrometry (HPLC–DAD-MS/MS). Local natural dyes, such as red and yellow from Morinda citrifolia, lac dye (Kerria lacca), gamboge (Garcinia sp.), turmeric (Curcuma longa), indigo and tannins were found in the older textiles, supporting a possible early production, whereas mixtures of natural and synthetic dyes, including synthetic alizarin (CI 58000), rhodamine B (CI 45170), orange I (CI 14600), diamond green B (CI 42000), diamond green G (CI 42040), auramine O (CI 41000), naphthol yellow S (CI 10316), chrysamine G (CI 22250), crystal violet (CI 42555) and Pigment Red 53:1 (CI 15585:1) were identified in the later textiles. Observations on mordants revealed the use of aluminium, tin and chrome, whereas fibre characterisation highlighted the use not only of cotton (Gossypium sp.) but also of felted wool imported from Europe and Chinese silk dyed with the Chinese cork tree (Phellodendron chinense) yellow dye. The results draw an interesting picture of the introduction of new dyeing materials and techniques in Myanmar over the nineteenth century, and how these impacted the production of traditional Karen textiles.

The Non-Invasive Characterization of Iron Age Glass Finds from the “Gaetano Chierici” Collection in Reggio Emilia (Italy)

This work reports the results of the analyses performed on a set of glass finds from the “Gaetano Chierici” collection in the Civic Museums of Reggio Emilia. Forty-eight typologically heterogeneous glass finds were included in the list of the analyzed objects, dating from the fifth century BCE to the first century CE. The objects primarily consisted of glass beads; however, bangles, pinheads, and one vessel fragment were also included in the set. The items were analyzed using non-invasive spectroscopic methods that were implemented with portable equipment on the museum’s premises. Fiber optic reflectance spectroscopy was used to identify the coloring species in the glass matrix, while X-ray fluorescence spectrometry provided compositional information. Both techniques allowed for a discussion of the mechanisms of coloring and opacification, as well as the raw materials used for this purpose. The results provided a complex picture of the various colorants used to manipulate the appearance of the glass, which was a crucial aspect in the creation of the personal adornments represented by these glass items. The data revealed evidence of different sources of raw glass and colorants. Most of the samples were colored with cobalt, but iron and copper also influenced the color of many of them. Both white and yellow were utilized for the glass decorations, and these colors were achieved with the addition of either antimony-containing crystals or tin-containing ones. This finding suggests that the transition from antimonate to stannate started as early as the second century BCE. The “Gaetano Chierici” collection contains representative objects distributed throughout the investigated period. The results obtained here are a starting point for future studies of glass technology and provenance in the area.

The Book of Uí Mhaine: An Interdisciplinary Analysis of the Materiality of the Gaelic Manuscript Tradition

This paper presents the findings of the first multi-analytical investigation of the Book of Uí Mhaine, one of the largest Gaelic Books surviving from the medieval vernacular period. A combination of protein analysis, point X-ray fluorescence spectroscopy (XRF), multispectral imaging (MSI), point Fiber-Optic Reflectance Spectroscopy (FORS) and point Raman spectroscopy was used to perform a systematic investigation of the Book of Uí Mhaine’s constituent materials, including parchment, inks and pigments. The analysis revealed that the parchment was made of calfskin, both blunt tools and Pb-containing materials were used for ruling the pages throughout the manuscript, and iron-based inks were used to write the content of the book. The decoration was restricted to the initial letters and rubrication across the body text. The decoration color palette was limited to yellow and red, comprising arsenic-, mercury- and lead-based pigments. A copper-based green pigment was found only on one folio. The scientific knowledge acquired through this multi-analytical approach complemented a substantial corpus of knowledge already built by Gaelic scholars, paleographers, codicologists and conservators. This work not only allowed for the consolidation of existing information on methods and materials used for the production of medieval Gaelic manuscripts but also laid the basis for future comparative work with other contemporary traditions in Ireland and Europe.

Applying Gel-Supported Liquid Extraction to Tutankhamun's Textiles for the Identification of Ancient Colorants: A Case Study.

The identification of the dyes present on a linen fragment from the tomb of Pharaoh Tutankhamun is the objective of the present study. Fiber optic reflectance spectroscopy (FORS) was applied to the archaeological sample for preliminary identification of the dyes and to better choose the extraction methodology for different areas of the sample. The innovative gel-supported micro-extraction with agar gel and the Nanorestore Gel® High Water Retention (HWR) gel were applied to the archaeological sample after testing of the best concentration for the extraction of the agar gels substrates, performed on laboratory mock-ups by means of UV-Vis transmittance spectroscopy. Immediately after extraction, Ag colloidal pastes were applied on the gel surface and Surface Enhanced Raman Scattering (SERS) analysis was performed directly on them. The combination of information deriving from FORS and SERS spectra resulted in the successful identification of both indigo and madder and, in hypothesis, of their degradation products.

First evidence and characterisation of rare chrome-based colourants used on 19th-century textiles from Myanmar

First evidence for the use of the chrome yellow dyeing method was obtained on late 19th-century Karen textiles from Myanmar. Non-invasive observations obtained by digital microscopy and fibre optic reflectance spectroscopy (FORS) provided hints of the possible presence of non-conventional organic colourants in yellow, orange and green threads used to produce three textiles under investigation. Micro-samples analysed by scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX) and micro-Raman spectroscopy enabled PbxCrOy formulations directly precipitated onto cotton fibres to be identified and characterised in these threads. Complementary analyses by high pressure liquid chromatography coupled to diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS) revealed that in the orange and green threads the chrome-based colourants were over-dyed with local natural dyes, thus revealing an unprecedented dyeing scenario, in which cotton threads imported from Europe were over-dyed locally by Karen people to obtain desired colour shades. Additionally, while yellow threads showed the presence of chrome yellow (lead chromate - PbCrO4), orange and green threads mostly contained chrome orange (basic lead chromate – Pb2CrO5 or PbCrO4·Pb(OH)2), which led us to hypothesise that chrome yellow partially transformed into chrome orange due to the over-dyeing process performed in alkaline conditions. This study raises awareness of the need for detailed spectroscopic characterisation coupled with high resolution mass spectrometric analysis to study complex mixtures of dyeing materials in historic textiles and has strong implications for advancing our understanding of the impact of British colonisation on traditional textile-making in Myanmar.

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.

New insights on Teotihuacan color technology: a proposal of a technological style for mural painting

Teotihuacan, the main city of the Classic period in Central Mexico (ca. 150/200–650 CE), was among many things, a colorful city. Through its application on mural painting, ceramics, lapidary, bone, textiles, and the human body itself, coloring materials gave meaning to the Teotihuacan reality. This research presents color as a socio-technological phenomenon from the archaeology of color, the anthropology of technology, and the application of the concept of technological style.From this scope, pictorial palettes of mural painting fragments from three Teotihuacan architectural compounds were studied by digital microscopy, colorimetry, fiber optic reflectance spectroscopy (FORS), X-ray fluorescence (XRF), Raman spectroscopy, infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) in order to identify the color technology of pigments. This approach led us to identify materials shared by the three studied compounds, red and yellow earths, cinnabar, malachite, pseudomalachite, azurite, and the Teotihuacan grayish blue, found to contain a mix of bone black with calcite. Our results contribute to the discussion on the use of raw materials and their mixtures. We observed a standardization of pigment technology in Teotihuacan mural painting through the use of shared and standard formulations with four indicators that we propose as markers of a technological style for pigments, along with variations in the color materials that evidence the use of different strategies for the procurement and distribution of raw materials among the diverse architectural assemblages of the city.

Non-Invasive Characterisation of the Wall Paintings in the Byzantine Church of Palazzo Simi (Bari, Italy) and Digital Photogrammetric Survey for a Pigment Mapping

The paper illustrates the results of a non-invasive characterisation of pigments and their mixtures in the pictorial surfaces of the wall paintings (10th century) found in the Byzantine church of Palazzo Simi in Bari (Italy). The investigation techniques included portable digital polarised microscopy, fibre optic reflectance spectroscopy (FORS) and X-ray fluorescence spectroscopy (XRF). Data comparison supported the recognition of red and yellow ochres, green earth, vine black, minium and Egyptian blue. The presence of some pigment mixtures demonstrated the recurrence of specific technical expedient used by local medieval artists in order to simulate more expensive pigments, which enabled contribution to the understanding of the valuable artistic tradition of the Apulian Middle Age. Both for purposes of conservation and fruition of the site, which is not always accessible, and due to the complexity in taking suitable photographs for the representation of results, the latter was performed on orthophotos extracted from a digital photogrammetric 3D model of the whole archaeological site. By means of chromatic overlapped layers, an interactive compositional map of the pictorial surfaces was produced.

An archaeometric contribution to the interpretation of blue-green glass beads from Iron age Central Italy

Several types of (mostly) blue-green glass beads from Iron-Age archaeological sites in Central Italy were studied using a range of spectroscopic techniques: portable X-Ray Fluorescence spectrometry, Fibre Optics Reflectance Spectroscopy, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectrometry, micro-Raman spectroscopy and Laser Ablation Inductively Coupled Plasma Mass Spectrometry. Complementary information was gathered from each technique and discussed in the frame of the archaeological typology of the objects. The systematic evaluation of the results allowed us to draw some conclusions on the raw materials employed for primary production and to highlight some provenance indicators in the glass. Some of the beads found in the Iron Age (IA) contexts were preliminarily attributed to the Final Bronze Age (FBA) production based on their typology, and the compositional data obtained in this work confirmed that they were low magnesium high potassium (LMHK) glass, typical of FBA in the Italian peninsula. Other beads were assigned to low magnesium glass (LMG) or high magnesium glass (HMG), thus giving further information on the fluxing agents employed in the Early Iron Age (EIA) and beyond. Colour variations among the beads reflected their chemical composition, with different bead typologies coloured in a specific way. In some instances, it was possible to establish different origins for the colouring raw materials. The provenance of the samples was difficult to place, but the chemical evidence suggested a subdivision within the raw glass used to produce the beads: for one set of samples, a local origin of the glass could be hypothesised, whereas several production sites in the Near East were suggested for most of the beads considered in this study. Some preliminary clues for the local working of imported glass were also highlighted for one typological group.

The atypical hues of the Santa Cruz blue-and-white cargo: non-invasive analysis of glaze defects and color variations in mid-Ming porcelain

Color variations and sometimes the frosted appearance of Chinese blue-and-white porcelain produced in folk kilns and recovered in underwater archaeological contexts are usually reported without further investigation. This study focuses on the causes responsible for the appearance of the glaze and blue decorations of late fifteenth-century blue-and-white porcelain from the Santa Cruz, one of the most important mid-Ming shipwrecks discovered in Asian waters. Besides detailed visual observations, chemical composition and colorimetric data were collected on a set of similarly shaped plates showing significant differences in the aspect of the glaze and tones and shades of the blue color. Results from portable X-ray fluorescence (pXRF) analysis confirmed the Jingdezhen origin of the ware and the use of domestic asbolane ores for the Co-based blue pigment. Visual and microstructural analysis has shown that the degree of opacity of the glaze is primarily linked to the crystallization of anorthite, which in some cases has pushed the pigment layer towards the surface, contributing to the development of white-brownish weathering spots. The colorimetric data acquired with fiber optics reflectance spectroscopy (FORS) allowed us to quantify chromaticity parameters and confirm the visual perception of a ‘not-so-blue’ color of the decoration. Without excluding a possible contribution of the underwater environment, the observed variations can be mainly attributed to the ware’s production and more specifically to pigment characteristics, manufacturing processes, and firing conditions even though the connection with these factors is not straightforward and prompts further research and broader discussions. From a historical perspective, it is suggested that the atypical hues are correlated with the progressive switch from foreign to domestic pigment sources during the Chenghua period (1465–87 CE) and the subsequent technological adaptations required by an ever-increasing demand for Chinese blue-and-white porcelain at the turn of the sixteenth century.

On Devotional Artworks: A Non-Invasive Characterization of Pigments of the Madonna della Croce Wall Painting in Triggiano (Bari, Southern Italy)

Devotional artworks represent a valuable form of art, as they are evidence of religious worship and the demo-ethno-anthropological, as well as historical-artistic, heritage of a community, which is why they definitely belong to the cultural identity of a geographic area. The Madonna della Croce wall painting is an example of devotional art preserved today in the homonymous church in Triggiano (Bari, Italy). The presented study concerns the characterization of pigments used in the painting. The identification of pictorial materials had the aim of providing a contribution to knowledge about the painting, the history of restorations, and other historical events, and to increase the information about the Apulian painting to better reconstruct the social, cultural, and economic contexts of the region. Through a non-invasive and fast methodological approach, including portable digital microscopy, colorimetry, fibre optic reflectance spectroscopy (FORS), and X-ray fluorescence spectroscopy (XRF); 42 points considered on coloured areas were analysed in situ, and results on pigment identification were achieved. According to the local wall painting tradition, red and yellow ochres, green earth, vine black, massicot, and lead-tin yellow were found. Furthermore, both indigo-woad dye and a mixture of vine black and yellow ochre to obtain a blueish colour on the Virgin’s mantle were highlighted.

Exceptional Illuminated Manuscripts at the Gulbenkian Museum: The Colors of a Bible and Three Gospels Produced in the Armenian Diaspora

The illuminated manuscripts at the Gulbenkian Museum were produced in the 17th century, in scriptoria of the Armenian diaspora. In this work, we selected analytical methods that can be used in situ to study the colors of the illuminations. Scientific analysis based on fiber-optics reflectance spectroscopy in the visible and Raman spectroscopy has shown the use of a medieval palette based on inorganic pigments such as lapis lazuli, minium, vermilion, orpiment, indigo, two different greens (vergaut and malachite), lead white and carbon black. More importantly, in this context, it showed that the very important reds and pinks are possibly based on carminic acid. The painting technique is, however, different, as are the ways of painting the faces, hands, and vestments. The range of colors in the Bible and the three Gospel Books, enhanced by lapis lazuli blue and organic reds and pinks, demonstrates a desire to create exceptional illuminated manuscripts.

Spectroscopic and mass spectrometry-based in-situ investigation of a 17th-century handwritten academic diploma on illuminated parchment

In 2008, more than 300 ancient scrolls, some of which were preciously illuminated, were recovered in Chicago (USA) after being stolen and illegally exported. These scrolls consisted of private and public documents, including papal and royal, dating from the 14th to the 19th century. The scrolls were returned to Italy and 42 of them, known as the Chicago Parchments, are now preserved at the State Archives of Bari (Italy). An illuminated academic diploma from the 17th century, known as doctoratus privilegium, was among them, and it was of particular interest to restorers and conservation scientists. To identify the pigments, painting binders, and animal skin origin of the parchment, non-invasive analyses were carried out on several points using portable X-ray fluorescence (XRF), µRaman, and fibre optic reflectance spectroscopy (FORS). Gold and silver decorations were confirmed by XRF, highlighting the significance of the document. A quasi-non-invasive sampling approach was used to analyze the painting binders by applying a trypsin-chymotrypsin enriched hydrogel for in situ digestion of the proteinaceous material. The extracted binders were successfully identified as bovine and rabbit glues by both matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry (MALDI-ToF-MS) and reversed-phase liquid chromatography with electrospray ionization tandem mass spectrometry (RPLC-ESI-MS/MS). By using bottom-up proteomics, the sheep skin origin of thin parchment samples was established from very small fragments that were digested in solution with trypsin.

A Non-Invasive and Sustainable Characterization of Pigments in Wall Paintings: A Library of Apulian Colors

This paper proposed a multianalytical, non-invasive, accessible and expensive (compared to traditional ones) approach for the characterization of pictorial surfaces. A set of 18 pigments and 37 mixtures widely used in the Middle Ages in the Apulia (Italy) artistic and archaeological contexts was considered, and corresponding replicas were produced. Pigments were first characterized by X-ray powder diffraction (XRPD), then replicas were studied by optical microscopy using a portable instrument, colorimetry and fiber optic reflectance spectroscopy (FORS). The investigation provided encouraging results, which allowed the creation of a library including diagnostic microscopic, colorimetric and reflectance markers of each pigment and the identification of the mixtures’ components.

Evaluation of the Irradiation Treatment Effects on Ancient Parchment Samples

In this work, the effect of X-ray irradiation as a disinfection treatment in original ancient parchment samples, belonging to a discarded book cover of a 16th-century archival register, has been evaluated. Specifically, the bacterial and fungal species isolated from the book cover have been characterized and then irradiated with increasing doses of X-rays with the aim to evaluate the effectiveness of the antimicrobial protocol on the isolated microorganisms. The deterioration effects induced by the X-ray treatment as well as the natural aging on the collagen matrix of the parchment sample have been tested by employing several techniques, namely, Light Transmission Analysis, Fiber Optic Reflectance Spectroscopy, Attenuated Total Reflectance-Fourier Transformed Infrared spectroscopy, UV Resonant Raman spectroscopy and Atomic Force Microscopy. The results reveal that the irradiation treatment applied to our ancient parchment samples deteriorated by biological attack and other naturally occurring phenomena, possibly associated with inappropriate conservation conditions, does not seem to induce further damage factors even when large doses of irradiation are employed. The X-rays-based disinfection treatment effects are limited on the collagen support and this confirms the potential of this method in mass disinfection of library and archival materials.

The Unexpected Discovery of Syngenite on Margarito d’Arezzo’s The Virgin and Child Enthroned, with Scenes of the Nativity and the Lives of the Saints (Probably 1263–4) and Its Possible Use as a Yellow Lake Substrate

The oldest painting in the National Gallery collection, The Virgin and Child Enthroned by Margarito d’Arezzo (NG564), dated to about 1263–4, depicts the Virgin and Child in a mandorla, surrounded by scenes of the Nativity and lives of the saints, set within red and decorative black borders, against a gilded background. The materials and technique were investigated using a combination of non-invasive techniques, such as Fibre Optic Reflectance Spectroscopy (FORS) and macro X-ray fluorescence scanning (MA-XRF), and the analysis of a small number of paint samples using energy dispersive X-ray analysis in the scanning electron microscope (SEM-EDS), High-Performance Liquid Chromatography (HPLC), Attenuated Total Reflectance—Fourier transform infrared spectroscopy (ATR-FTIR) and micro X-ray Diffraction (micro-XRD). The results provided evidence for the use of a number of organic colourants, with both indigo and red lake pigments identified. The finding of an unusual compound, syngenite (K2Ca(SO4)2·H2O), is here postulated as a potential substrate for an organic yellow lake pigment. In addition, reference pigments were prepared to explore this hypothesis. Although documentary evidence confirms that yellow lakes were being produced from an early date, there is very little direct evidence for their use in 13th-century panel paintings.

Dye Identification in Mounting Textiles of Traditional Korean Paintings from the Late Joseon Dynasty

In the framework of the ‘Amorepacific Project for the conservation of Korean pictorial art’ (2018–2023) at the British Museum, three traditional Korean paintings have been investigated with the aim of supporting their conservation and obtaining information about the dyes used in the mounting textiles and other mounting elements. The paintings include a rare example of late 18th-century traditional Korean portraiture (accession number 1996,0329,0.1); a late 19th-century two-panel screen silk painting of Pyeongsaeng-do-Scenes of life (accession number 2016,3028.1); and a late 19th-century twelve-panel screen silk painting representing the Five Confucian virtues (accession number 1957,1214,0.1). The mounting textiles were investigated non-invasively by using digital microscopy and fibre optic reflectance spectroscopy (FORS), and the results guided a minimally invasive sampling campaign. Fourteen samples were analysed by using high-pressure liquid chromatography coupled with diode array and tandem mass spectrometry detectors (HPLC-DAD-MS/MS), leading to the identification of the natural dyes indigo, sappanwood (Biancaea sappan, formerly Caesalpinia sappan), amur cork tree (Phellodendron amurense) and safflower (Carthamus tinctorius) in the mounting elements of the 18th-century portrait. These results confirmed some of the non-invasive observations and were in agreement with the production date of the painting. Both natural and synthetic dyes were identified in the mounting textiles of the panel screens. Among the synthetic dyes, fuchsin (C.I. 42510), methyl violet 3B (C.I. 42536), methyl blue (C.I. 42780) and benzopurpurin 4B (C.I. 23500) were identified. These are early synthetic dyes first synthesised between the 1860s and the 1880s, suggesting that the silk textiles are likely to have been dyed in the last part of the 19th century.

Ring-eye blue beads in Iron Age central Italy – Preliminary discussion of technology and possible trade connections

The Iron Age was a remarkable period in glass technology development and its spread across the Mediterranean. Communities that populated what is nowadays Central Italy underwent profound changes during this period forming more complex societies, developing proto-urban and urban centres, and incorporating into a wide trade network of the Mediterranean Sea and beyond. Glass objects in that small region are frequently found in burial sites dated to the first half of the first millennium BCE, with small blue beads with simple ring eyes being among the most abundant types. Fifty-six objects of this type (both whole beads and fragments) were studied with a non-invasive approach by means of Optical Microscopy, Fibre Optics Reflectance Spectroscopy, and portable X-ray Fluorescence spectroscopy. The analyses were conducted at the Museo Nazionale Etrusco di Villa Giulia and at the Museo delle Civiltà (both in Rome, Italy). Five samples from the main set were also analysed with a Scanning Electron Microscope coupled to an Energy Dispersive Spectrometer. The data gave preliminary information on the raw materials used to prepare the glass, the manufacturing techniques, and offered some hints to (tentatively) locate the region of provenance. In particular, the analyses established that the beads are soda-lime-silica glass and the source of cobalt, used as the blue colorant, could be an ore from Egypt. Within this general frame, a smaller group showed a different compositional pattern. These preliminary results contribute new knowledge for tracing exchange routes within the Mediterranean during the Iron Age.

Spectroscopic and Morphologic Investigation of Bronze Disease: Performance Evaluation of Portable Devices

Copper alloy artworks are particularly subjected to chloride attack, which may trigger bronze disease. Therefore, early identification of the phenomenon is crucial in order to stabilize the reactive copper chloride (CuCl) and remove the harmful corrosion products (atacamite and polymorphs). Confocal Raman Microspectroscopy (CRM) has proven to be effective for the detection of small amounts of atacamite, ascribable to the initial phases of corrosion. The handling of bronze artworks is often difficult or even impossible given their large size and weight, and sampling is not always allowed, making the use of portable instruments mandatory for on-site diagnostics. This paper proposes a method for the early detection of corrosion using non-invasive approaches. In this work, we present the results obtained from a set of artificially aged bronze samples with a suite of either laboratory (bench-top) or field (portable/transportable) instruments with the aim of highlighting their characteristics and performances in the diagnosis of bronze disease. Raman spectroscopy, Fiber Optics Reflectance Spectroscopy (FORS), Optical Coherence Tomography (OCT), and Scanning Electron Microscopy (SEM) were applied for chemical and morphological characterization of the samples.

From Materials to Technique: A Complete Non-Invasive Investigation of a Group of Six Ukiyo-E Japanese Woodblock Prints of the Oriental Art Museum E. Chiossone (Genoa, Italy).

In the present work, a complete non-invasive scientific investigation of six Utagawa Kunisada's woodblock prints (nishiki-e) belonging to the Oriental Art Museum "E. Chiossone" (Genoa, Italy), was performed in situ. The campaign started with high resolution multiband imaging (visible, multiband fluorescence, near infrared) followed by reflectance transformation imaging (RTI) to characterize and highlight the peculiar printing techniques and the condition of the support. Then fiber optics reflectance spectroscopy (FORS), spectrofluorimetry, Raman and reflectance Fourier-transform infrared (FTIR) spectroscopies were successfully applied in synergy for the investigation of the printing materials (pigments, binders, support). The results obtained represent a set of very important information for these never-before-studied works of art, useful to the different professionals involved: historians, conservators and curators. The materials identified were completely in agreement with those traditionally used in the Edo period in the 19th century, while the computational imaging technique RTI gave an additional amount of information in terms of surface characterization that could not be overlooked when studying these works of art. RTI data were further processed to enhance the texture visualization.