Subterranean Cultural Heritage sites are frequently subject to biological colonization due to the high levels of humidity, even in conditions of low irradiance and oligotrophy. Here microorganisms ...form complex communities that may be dangerous through mineral precipitation, through the softening of materials or causing frequent surface discolorations. A reduction of contamination’s sources along with the control of microclimatic conditions and biocide treatments (overall performed with benzalkonium chloride) are necessary to reduce microbial growths. Dark discolorations have been recorded in the painted Etruscan tombs of Tarquinia, two of which have been analyzed to collect taxonomical, physiological, and ecological information. Eighteen dark-pigmented fungi were isolated among a wider culturable fraction: nine from blackening areas and nine from door sealings, a possible route of contamination. Isolates belonged to three major groups: Chaetothyriales, Capnodiales (Family Cladosporiaceae), and Acremonium-like fungi. Exophiala angulospora and Cyphellophora olivacea, a novelty for hypogea, were identified, while others need further investigations as possible new taxa. The metabolic skills of the detected species showed their potential dangerousness for the materials. Their tolerance to benzalkonium chloride-based products suggested a certain favouring effect through the decreasing competitiveness of less resistant species. The type of covering of the dromos may influence the risk of outer contamination. Fungal occurrence can be favoured by root penetration.
•Tolerance to biocides affects fungal spreading.•Metabolic screenings show fungal dangerousness for materials.•Subterranean environments show unknown fungal taxa.
In Roman wall paintings, blue and green colours are less commonly encountered than red and yellow and were more expensive. Despite this, Pliny and Vitruvius describe the more common compounds used ...for these pigments, translated today as azurite, lazurite, chrysocolla, indigo and Egyptian blue for blues and verdigris, malachite, celadonite, glauconite and chlorite for greens. A confusion in their nomenclature is often found in the most common blue pigment that is the first manufactured compound, Egyptian blue. For greens, celadonite and glauconite were usual and called generically ‘green earths’, but they prove to be difficult to characterize analytically. In this paper, we evaluate the Raman spectroscopic identification of the characteristic Roman blue and green pigments as used in wall paintings using two different laser wavelengths (green and near infrared) and clarify their nomenclature.
Green and blue pigments were scarce and valuable in the Roman wall paintings. Raman spectroscopy is a useful technique for identifying blue and green compounds even in admixture with other minerals. We used two lasers, 780 and 532 nm, which improve the identification probabilities. We discuss the differences between the spectra collected with each laser for each compound and also the right characterization among the greens and blues.
In this paper, diagnostic analyses on 12th–13th century byzantine wall paintings in the abbey of Santa Maria di Cerrate (Southern Italy) were carried out preparatory to restoration work promoted by ...FAI (Fondo Ambiente Italiano). Both the pigments and the areas with a bleaching alteration in the frescoes were analysed using the energy dispersive X-ray fluorescence, the Raman spectroscopy and the scanning electron microscopy equipped with energy dispersive X-ray spectrometer. In particular, ED-XRF analyses were performed in situ on wall paintings, while Raman spectroscopy and SEM-EDX were accomplished on frescoes fragments. The results obtained allowed to determine the chemical composition of the pigments, helping to identify the original parts of the frescoes from the retouched ones. The work also provided important information about the historical-artistic context of the abbey. Archaeometric investigations have indeed revealed the pictorial technique used for the wall paintings of the abbey, as well as the presence of some very valuable pigments, such as lapis lazuli blue.
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•Archaeometric investigations of Byzantine wall paintings in view of their restoration•ED-XRF, Raman spectroscopy and SEM-EDX to distinguish original pigments and retouched parts•Characterization of pigments and byzantine techniques•Blue of lapis lazuli extensively used in the wall paintings•Bleaching alterations produced by photocatalytic action of titanium oxide
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•Scientific knowledge of the palette and technique of Roman wall paintings of Ostia Antica.•Use of optimized protocol integrating both non-invasive and microinvasive ...techniques.•Analogies and differences in the materials employed correlated to the different styles.•An important source of information for future research especially for the wall paintings still in place.
This paper presents the study of selected painted fragments from different contexts of Ostia Antica city, dating between 2nd century BCE and the end of the 1st century CE. The aim is to identify the raw materials used and to understand the execution techniques through a non-invasive protocol including techniques based either on multiband imaging (Visible-VIS, Ultraviolet induced Luminescence - UVL and Visible Induced Luminescence - VIL) and single spot analyses (Fiber Optic Reflectance Spectroscopy- FORS and portable X-Ray Fluorescence spectrometry - XRF). The most representative and interesting fragments were sampled for further studies with laboratory techniques such as optical microscopy (OM) and electron microscopy (SEM), Fourier Transform Infrared and micro-Raman Spectroscopies (FT-IR and μRaman).
The extensive use of non-invasive techniques, even working on fragments, is proved to be the most robust and effective approach enabling the analysis of a high number of areas, dramatically increasing the statistical meaning of the collected data. The elaboration of such a huge number of data allows highlighting differences and similarities, thus achieving a more realistic overview of the materials composition and addressing the sampling to the more significant and complex areas.
•Early Medieval wall paintings from the Raetia Curiensis Region.•Application of non-invasive scientific methodologies for the documentation and analysis of wall paintings.•Detection of pigments in ...the crypt of the church of St Stephan in Chur in the transition period between Roman and Medieval time.•The painted stucco fragments from the church of St Martin in Disentis surprisingly indicated the absence of green and blue pigments.
The Early Medieval wall paintings preserved in historical sites of the ancient Raetia Curiensis region (today's Swiss Canton of Grisons and parts of Northern Italy and Austria) provide a rare testimony of the art of this period.
This contribution presents the results of the non-invasive scientific campaigns carried out in the churches of St. Stephan in Chur and St. Martin in Disentis/Mustér (Canton of Grisons, Switzerland). In the church of St. Stephan, the investigations were performed in-situ on the surviving wall paintings of the crypt and on several painted plaster fragments (crypt and upper church), while in Disentis a selection of painted stucco fragments was studied. All the painted surfaces were firstly examined with technical photography in visible, infrared, and ultraviolet ranges, followed by portable spectroscopic point analyses (i.e. HH-XRF, FORS, and FTIR). The findings revealed the composition of most pigments such as iron-based pigments (yellow and red ochres, green earth) and lead-based pigments (i.e., lead white and red lead). In addition, for the St. Stephan's site, the Visible Induced IR Luminescence (VIL) images combined with point analyses, allowed for the identification of Egyptian blue (EB). Furthermore, the presence of zinc in the wall paintings of the crypt of St. Stephan and the absence of this element in those referable to the upper church, suggested differences in the procurement of copper for the manufacture of EB. The presence of arsenic and lead in iron-bearing pigments detected in the wall paintings of the crypt and their negligible amount in those of the upper church, suggested that these pigments come from a different sourcing area.
In the church of St. Martin, the use of different pigments for the execution of the incarnate of the figures, the extraordinary state of conservation of minium, and the absence of green and blue pigments are remarkable features of the stucco decoration paintings.
Preserving ancient wall paintings from damage has become a challenge over the years. Nanosized calcium hydroxide (Ca(OH)2) has been identified as a promising material to preserve wall paintings. ...However, the synthesis of nanosized Ca(OH)2 is extremely difficult. Here, we demonstrate a breakthrough in wall painting protection enabled by boron nitride nanosheets (BNNSs) through strategic synthesis Ca(OH)2-BNNS nanohybrids using an aqueous method. The BNNS have two significant functionalities in the design and implementation of the Ca(OH)2 nanomaterials. First, the introduction of BNNS results in the successful synthesis of uniform and nanosized Ca(OH)2 (∼80 nm) in the nanohybrids, which can be attributed to the supersaturation-induced “etching–stripping” mechanism. More interestingly and importantly, a unique gradient penetration structure is strategically formed when applying Ca(OH)2-BNNS hybrids on the wall paintings, i.e., the BNNS-rich layer will be at the surface of wall painting, whereas Ca(OH)2 nanomaterials prefer to penetrate deep in to the wall paintings. This gradient structure will allow the BNNS-rich layer to protect the wall paintings from fire, which is the first report to date among the protection materials for wall paintings; at the same time, nanosized Ca(OH)2 shows superior wall painting consolidation strength compared to commercial Ca(OH)2 material. These results endow new applications of the newly emerging two-dimensional nanomaterials for protecting cultural heritage.
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•In-depth knowledge of Paestum funerary art wall painting (Italy).•Discovery, for the first time, of calcium antimonate particles on wall paintings.•Involvement of iron oxidation in ...the green hues discoloration.•Demonstration of the use of “fresco” painting technique.•Confirmation of ceramic painters’ involvement according to archaeologists’ hypothesis.
During a restoration and diagnostic campaigns carried out on Paestum funerary slabs belonging to the Lucanian funerary art, calcium antimonate (CaSb2O6) was detected for the first time in the pictorial layers. This artificial pigment, widely employed as opacifier both in ancient glass and glaze covering clay objects, was found in the wall paintings, regardless of the colour, supporting the hypothesis of an intentional addition of calcium antimonate to the pigments and the involvement of ceramic painters.
A multi-analytical approach was performed on 32 funerary slabs (6th – 3rd century BCE), currently located at the National Archaeological Museum of Paestum (Italy) using both polarized light microscopy and environmental scanning electron microscopy equipped with energy dispersive X-ray spectrometer, micro X-ray fluorescence, micro Raman spectroscopy, Fourier Transform Infrared spectroscopy and powder X-ray diffraction.
The results confirmed the use of a limited number of pigments, usually applied with fresco technique, although in many cases the stratigraphy of the painted layer showed morphology of mezzo fresco technique, but no organic binders were found. The hues of vegetal decorations were obtained using green earth, sometimes Egyptian blue mixed with yellow ochre, carbon and bone blacks, and orpiment. The alteration of green earth and other iron-containing pigments are likely responsible for the discolouration of the original hues. In red paints, hematite and red ochre are frequently associated with ilmenite, a typical volcanic mineral. Egyptian blue was used in blue paints while in black paints it was mixed with carbon and bone black pigments.
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•DMSNs/Au nanocomposites for loading electrochemical signal probes was synthesized.•A electrochemical sensor for simultaneously detecting two binders was developed.•An archaeological ...sample was detected using both ELISA and constructed sensors.•The sensor has great meaning to research the component of ancient wall paintings.
In this study, a label-free and double signal Au modified dendritic mesoporous silica nanoparticles (DMSNs/Au) tag modified electrochemical immunosensor were developed and applied for simultaneously detecting ovalbumin from egg white and casein from milk that are likely to exist in ancient wall paintings. This sensing strategy was designed by introducing two different signals tag based on Au modified DMSNs with porous structure to distinguish corresponding electrochemical signals. The DMSNs with porous structure not only adsorb more electrochemical redox probes, but also immobilize more antibodies, which significantly improved sensitivity of biosensor. Under optimal experiment conditions, the fabricated immunosensor demonstrated excellent performance in the analysis of ovalbumin and casein, with a detection limit of 0.59 ng·mL−1 and 0.36 ng·mL−1, respectively. Finally, the designed sensors were successfully applied to analyze real archaeological samples for evaluating the presence of egg-based, milk-based, or mixed binders in the samples. The proposed immunosensor provides a novel protocol for the analysis and detection of cultural relic materials.
This study aimed at using portable analytical techniques to characterize original and decayed materials from two murals paintings of Ariadne House (archaeological site of Pompeii, Italy) and define ...the degradation pathways threatening their conservation. The first wall, located in an outdoor environment, has been directly exposed to degradation processes triggered by weathering and atmospheric pollution. The second wall, placed in a basement under the ground floor, has been constantly sheltered from sunlight exposure and drastic temperature fluctuations. The analytical data obtained in-situ by using Raman spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS) correlates the degradation patterns affecting the two surfaces to their environmental context. The deterioration processes detected on the outdoor wall, which entailed the complete loss of the paint layer, were mostly related to leaching and thermal fluctuation phenomena. The mural painting from the basement instead, showed deep degradation issues due to soluble salt infiltration and biological colonization. The results obtained from this unique case of study highlight the indispensable role of in-situ spectroscopic analysis to understand and predict the degradation pathways jeopardizing the cultural heritage and provide to the Archaeological Park of Pompeii important inference to consider in future conservation projects.
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•This work aimed at identifying the degradation pathways jeopardizing two Pompeian mural paintings.•Raman and Laser Induced Breakdown Spectroscopy portable systems enabled the characterization of original and decay materials.•The strong link between the degradation patterns affecting the wall paintings and their environmental context was proved.
In the Late Bronze Age, in Second Millennium B. C., very important civilizations had flourished in the Aegean Islands and shores, such as the one of Akrotiri, Thera, of the Minoan Crete and of the ...Mycenean Boeotia. One of the main characteristics of these civilizations was the widespread Art of Wall Painting. In the present work, the method of drawing of a number of celebrated wall-paintings belonging to the three (3) aforementioned civilizations is studied. The authors have demonstrated that the entire set of the borderlines of all figures appearing in the studied frescoes, have been drawn by six (6) geometric stencils-guides, namely four (4) hyperbolae and two (2) Archimedes (linear) spirals, the conception and construction of which was impressively and extraordinarily advanced for the specific era. The conception and construction of these mathematical curves was, so far, believed that it took place at least one thousand four hundred (1400) years later by “giants of thought, Geometry and Mathematics” in the Classical Era.
