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Aceto M.,University of Piemonte Orientale | Agostino A.,University of Turin | Fenoglio G.,University of Turin | Idone A.,University of Turin | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2017

The Coronation Gospels or Krönungsevangeliar is a manuscript kept in Vienna at the Kunsthistorisches Museum Wien, datable to the end of VIII century A.D. and produced at Charlemagne court. It is an example of a purple codex, i.e. its parchment is coloured in purple. It has to be considered as one of the most important medieval codices, according to its use to take oath in the coronation ceremony of kings and emperors of the Holy Roman Empire up to 1792. In order to gather information of the manufacture of the manuscript and its present conservation state, a diagnostic investigation campaign has been carried out in situ with totally non-invasive techniques. X-ray Fluorescence Spectrometry (XRF), UV-visible diffuse reflectance spectrophotometry with optical fibres (FORS), spectrofluorimetry, optical microscopy and multispectral analysis have been applied in order to identify the colourants used in the decoration of the manuscript, with the main concern to the dye used to impart the purple hue to the parchment. The information collected was useful in order to address some of the questions raised by art historians concerning its history. © 2016 Elsevier B.V.


Aceto M.,University of Piemonte Orientale | Cala E.,University of Piemonte Orientale | Agostino A.,University of Turin | Fenoglio G.,University of Turin | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2017

The identification of the two purple dyes folium and orchil has rarely been reported in the analysis of painted artworks, especially when analysing illuminated manuscripts. This is not consistent with the fact that ancient literary sources suggested their use as substitutes for the more expensive Tyrian purple dye. By employing non-invasive spectroscopic techniques, the present work demonstrates that these dyes were actually widely used in the production of ancient manuscripts. By employing UV–visible diffuse reflectance spectrophotometry with optic fibres (FORS) and spectrofluorimetry, the abundant identification of both dyes on medieval manuscripts was performed by comparing the spectra recorded on ancient codices with those obtained on accurate replicas of dyed or painted parchment. Moreover, examples are also reported whereby the considered purple dyes were used in mixtures with other colourants. The overall information obtained here allowed us to define new boundaries for the time range in which orchil and folium dyes were used which is wider than previously thought, and to focus on their particular uses in the decoration of books. © 2016 Elsevier B.V.


Aceto M.,University of Piemonte Orientale | Arrais A.,University of Piemonte Orientale | Marsano F.,University of Piemonte Orientale | Agostino A.,University of Turin | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2015

Folium and orchil are dyes of vegetal origin. Folium is obtained from Chrozophora tinctoria (L.) A. Juss., whereas orchil is obtained from Roccella and other genera of lichens. These dyes were used in the past to impart purple hue to paintings and textiles as substitutes for the more prised Tyrian purple dye, obtained from shellfish. Despite several citations in ancient technical treatises dating back at least to the Greek-Roman age, the identification of these dyes in artworks is rare. In the case of folium, an additional drawback is that its composition is presently unknown. In this work different non-invasive (FT-IR, FT-Raman, fibre optic reflectance spectrophotometry, spectrofluorimetry, X-ray fluorescence spectrometry) and micro-invasive (surface enhanced Raman spectroscopy, matrix assisted laser desorption ionisation-time of flight-mass spectrometry, inductively coupled plasma-mass spectrometry) techniques were used in order to increase the diagnostic information available on these dyes. Measurements were carried out on the dyes extracted from raw materials and on painted or dyed parchments. The possibility to distinguish between folium and orchil by chemical analysis is discussed. © 2015 Elsevier B.V. All rights reserved.


Aceto M.,University of Piemonte Orientale | Idone A.,University of Piemonte Orientale | Idone A.,Laboratorio Analisi Scientifiche | Agostino A.,University of Turin | And 4 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Purple codices are among the most relevant and prestigious book productions of Late Antique and Medieval age. They usually contained texts from Holy Writings written with golden or silver inks on parchment dyed in a purple hue. According to the tradition, the colour of parchment was obtained by the well renowned Tyrian purple dye. From the material point of view, however, very little is known about the compounds actually used in the manufacture of these manuscripts. Presently, the information available is limited to the ancient art treatises, with very few diagnostic evidences supporting them and, moreover, none confirming the presence of Tyrian purple. It is more than apparent, then, the need to have at disposal larger and more complete information at the concern, in order to verify what came to us from the literary tradition only. In this study, preliminary results are presented from non-invasive investigation on a VI century purple codex, the so-called Codex Brixianus, held in the Biblioteca Civica Queriniana at Brescia (Italy). Analyses were carried out with XRF spectrometry, UV-visible diffuse reflectance spectrophotometry, molecular spectrofluorimetry and optical microscopy. The results suggest the hypothesis that Tyrian purple had been used as a minor component mixed with other less precious dyes such as folium or orchil. © 2013 Elsevier B.V. All rights reserved.


Idone A.,University of Piemonte Orientale | Idone A.,Laboratorio Analisi Scientifiche | Gulmini M.,University of Turin | Henry A.-I.,Northwestern University | And 5 more authors.
Analyst | Year: 2013

Surface-enhanced Raman spectroscopy (SERS) is an ideal tool for analyzing dyes on historical textiles because it requires very little sample compared to other available analytical methods and analysis can be done directly on the fiber. This paper reports on the first systematic study of the use of citrate-reduced silver colloidal pastes for the direct, extractionless, non-hydrolysis detection of dyes directly on wool, silk, cotton, and flax fibers. This type of study provides greater insight into the optimal conditions required for accurate analysis of dyes in historical samples. In this work, Ag colloidal pastes were characterized using localized surface plasmon resonance and scanning electron microscopy. The pastes were then employed for SERS analysis of twelve reference samples of different vegetal and animal fibers dyed with cochineal and eleven dyed with brazilwood. Furthermore, six historical textiles from an important collection of Mariano Fortuny (1871-1949) textiles at the Art Institute of Chicago were also examined, to test the efficacy of the paste on aged samples, and to shed light on Fortuny's fascinating production techniques. A mixture of cochineal and brazilwood was detected in some of the historical samples demonstrating, for the first time, simultaneous identification of these colorants used in combination. In addition, the findings give substance to the claim that Fortuny kept using natural dyes at a time when many new and attractive synthetic products became available. © 2013 The Royal Society of Chemistry.


Gulmini M.,University of Turin | Idone A.,University of Piemonte Orientale | Idone A.,Laboratorio Analisi Scientifiche | Diana E.,University of Turin | And 3 more authors.
Dyes and Pigments | Year: 2013

The dyers of the past exploited a number of natural dyestuffs and dyeing procedures to obtain countless beautiful colours. It is hard to disclose which dyestuff has been used to dye a historical or an archaeological textile through non-invasive analytical techniques; therefore invasive analytical strategies, which require sampling, are generally employed to face this task. Some useful indication may nevertheless derive from the electronic transitions of dyes supported on the fibres and the signals can be easily recorded by reflectance spectroscopy in the visible range of the electromagnetic spectrum. The use of portable instruments equipped with fibre optics allows operation in-situ directly on the surface of the samples, through a non-invasive approach which is particularly suitable for the inspection of historical or archaeological samples. In this paper, the strong and weak points of visible fibre optics reflectance spectroscopy are discussed, in order to highlight its possible application as a first non-invasive step of a multi-technique analytical strategy devoted to the recognition of natural dyestuffs in ancient textile artefacts. Visible fibre optics reflectance spectra were collected from a large set of reference samples (wool and silk) coloured through various dyestuffs and dyeing procedures, in order to identify the signals of the coloured species that impregnate the fibres. The position of minimum, maximum and inflection points in the reflectance spectrawas evaluated and critically discussed, in order to identify the signals which are not contingent to dyeing procedures or to the fibre typology, and that can be therefore confidently used for analytical purposes. In particular, wavelength intervals were defined, in which the characteristic signals of the investigated dyestuffs (indigo, woad, Saxon blue, logwood, cochineal, madder, brazilwood, old fustic, weld, turmeric and saffron) are expected. It emerged that visible fibre optics reflectance spectroscopy is poorly selective for yellow dyes based on curcumins and flavonoids, while it generally succeeds in detecting the other dyestuffs considered herein. The information obtained from the reference sample set was then exploited to analyze an embroidered cloth dated from the seventeenth century. Preliminary information obtained via visible fibre optics reflectance spectroscopy was confirmed, or integrated, by the results obtained through liquid chromatography coupled with diode-array detection and mass spectrometry on extracts obtained from some coloured threads sampled from the historical cloth. © 2013 Elsevier Ltd.


Idone A.,Laboratorio Analisi Scientifiche | Idone A.,University of Piemonte Orientale | Aceto M.,University of Piemonte Orientale | Diana E.,University of Turin | And 2 more authors.
Journal of Raman Spectroscopy | Year: 2015

Cross sections are very useful in the scientific investigation of paintings and polychromies as they show the sequence of the layers and allow the detection of colorants in each layer through micro-Raman spectroscopy. Surface-enhanced Raman scattering (SERS) presently represents the most promising tool to overcome the limits of a traditional micro-Raman approach in the investigation of painting materials containing fluorescent organic dyes. Among the SERS substrates, silver colloidal pastes are suitable to analyze minute samples by drop-coating them with the paste, without the need of specific pretreatments. The application of silver colloidal pastes has been explored here on two cross sections obtained from the 13th century painted wooden statue and from the 16th century mural painting. The main issue when employing such a substrate consists in achieving a suitable coating on the complex surfaces under investigation. In this work, some tests were devoted to enable the display of coated samples through the microscope coupled to the Raman spectrometer and to enhance the signals from lake pigments. The analytical procedure was successful in gaining SER spectra from the sections: the red, highly fluorescent pigment grains were identified as lake pigments obtained by kermes and by a purpurin-rich plant dyestuff. SER signals were discussed by considering SER spectra obtained from pure substances and/or reference materials and data reported in the literature. The work represents a further step toward the possibility of fully exploiting the high spatial resolution of the micro-Raman spectrometer to investigate samples from painted objects. Copyright © 2014 John Wiley & Sons, Ltd.


Aceto M.,University of Piemonte Orientale | Agostino A.,University of Turin | Fenoglio G.,University of Turin | Idone A.,University of Piemonte Orientale | And 6 more authors.
Analytical Methods | Year: 2014

The use of ultraviolet and visible diffuse reflectance spectrophotometry as a preliminary technique in the investigation of illuminated manuscripts is discussed. Because ancient manuscripts are amongst the most fragile and precious artworks, characterisation of the materials used in their decoration should be performed using non-invasive analytical methods. Ultraviolet and visible reflectance spectrophotometry with optical fibres (FORS) allows non-invasive identification of several colourants used by ancient illuminators, causing no damage or mechanical stress to the artworks subjected to analysis. Identification is usually based on the comparison of analytical data with a spectral database built from painted areas on parchment, created by preparing paints according to ancient recipes as described in medieval technical treatises. Such database and the spectral features of the colourants analysed are discussed, along with the benefits of extending the spectral range of analysis into the shortwave infrared (to 2500 nm). FORS can be best appreciated as a rapid preliminary tool that offers an overview on the main colourants employed and guides the selection of painted areas of manuscripts on which more selective techniques, such as X-ray fluorescence or Raman spectroscopy, can be employed for a more complete and accurate identification. © 2014 The Royal Society of Chemistry.


Favero-Longo S.E.,University of Turin | Sandrone S.,University of Turin | Matteucci E.,University of Turin | Appolonia L.,Laboratorio analisi scientifiche | Piervittori R.,University of Turin
Science of the Total Environment | Year: 2014

Fungal particulates are a dominant component of the bioaerosol, but aerobiological studies traditionally focused on a limited set of fungi having relevance as allergens or plant pathogens. This study first analyzes the occurrence of lichen meiospores in the mycoaerosol, quantitatively evaluating in the atmosphere of an alpine environment the occurrence of polar diblastic spores, unequivocally attributable to the lichen family Teloschistaceae. The analysis of air-samples collected one week per month for one year with a Hirst-type sampler displayed a low percentage occurrence of polar-diblastic spores (<. 0.1%) with respect to the whole mycoaerosol, dominated by Cladosporium. Spearman's correlation tests on aerobiological and climatic data highlighted a strong relationship between the detection of Teloschistaceae spores and rainfall events, excluding seasonal patterns or daily rhythms of dispersion. The fact that all the air-sampled spores were attributable to the species of Teloschistaceae occurring in the site, together with laboratory observations of predominant short range dispersal patterns for polar diblastic and other lichen spores, indicated that sexual reproduction is mostly involved in the local expansion of colonization, dispersal from a long distance appearing a less probable phenomenon. These findings indicated that responses of lichen communities to climate factors, usually related to physiological processes, also depend on their influence on meiospore dispersal dynamics. Spatial limitations in dispersal, however, have to be taken into account in evaluating lichen distributional shifts as indicators of environmental changes. © 2013 Elsevier B.V.

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