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1.
Lava columns from the cathedral St Maria of Randazzo (Catania, Italy), were studied in order to establish the classification of these rocks and to investigate their origin. At the beginning of the XIX century, some columns of the old frame of the nave were removed to build the dome and stored in a fornix beneath the cathedral. Samples were taken directly from these columns. The specimens underwent petrographic investigation through optical microscopy, X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR) and chemical analyses of major and trace elements through X-ray fluorescence (XRF). Some trace element (Sr, Rb, Y, Zr and Nb) concentrations were assessed through non-destructive analyses, performed with a portable X-ray device which can detect homogeneous concentrations of such elements on the columns of the cathedral. According to chemical data, these rocks can be classified as mugeariites whose mineral assemblage is given by plagioclase (mostly andesinic), augitic pyroxene, olivine, magnetite and, occasionally, apatite. In order to investigate the origin of the material used for the columns, a comparative examination was conducted between the column samples and specimens collected from quarries in the surrounding area of the town of Randazzo (Randazzo and Maniace quarries and the 1536 lava flow). The correlation with the Randazzo quarry proved to be excellent.  相似文献   

2.
The preservation of early 20th century, late 19th century albumen prints is of great concern to collection managers and conservators of photographic materials. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopic imaging is presented for the first time as analytical methodology for the study of albumen photographs. This paper shows the feasibility of obtaining FTIR images of samples from albumen photographs with a high spatial resolution using a Ge ATR objective coupled with an infrared microscope. The improved spatial resolution compared to FTIR images obtained by the reflection method is due to the high refractive index of the ATR crystal, which gives a high numerical aperture and hence, a higher spatial resolution. The technique reveals detailed information on the organic functional group distribution in the individual layers of embedded cross sections and is used complementary to visual microscopy and scanning electron microscopy/energy dispersed X-ray spectroscopy. The main results of the study are discussed with regard to their historical and artistic significance, and they are compared with data from historical and conservation literature.  相似文献   

3.
From 18 archaeological sites of the Lagoon of Venice 75 bricks belonging to Roman and medieval building levels have been analysed. Chemical composition and geometric measures allow the characterization of a group of 24 Roman bricks of Imperial age. The group formed by means of fuzzy c-means cluster analysis applied on chemical data have been tested by principal component analysis and finally subjected to discriminant analysis to estimate the relative weights of original variables and classify new elements. Correlations among the data of the major chemical elements confirm the reliability of the complex of chemical data. The aim of this research was to obtain a chemical characterization of Roman bricks (and later, of the medieval ones) coming from the lagoon of Venice thus making it possible: 1) to recognize the age of a brick by means of its chemical analysis; 2) to date the layers of archaeological excavations or the ground where there are medieval building foundations by means of membership bricks; 3) to calculate the rate of local ground lowering in the elapsed years by the difference in level from one layer to another; 4) to estimate local rates of land subsidence by comparison with mean values already known.  相似文献   

4.
A new laser-based spectroscopic technique, called calibration-free LIPS (laser-induced plasma spectroscopy), is proposed for fast and precise elemental analysis in the field of cultural heritage conservation and study. Quantitative stratigraphic results, obtained by CF-LIPS on ancient Roman frescoe samples, are shown. The application of this calibration-free procedure frees the LIPS technique from the need of reference samples or an internal standard. This characteristic, along with the intrinsic speed (the whole process of data collection and analysis takes a few minutes) and precision (of the order of a few parts percent) make the CF-LIPS a viable technique for in situ quantitative analysis of artworks.  相似文献   

5.
The utilization of laser light to produce fine and selective cleaning of superficial deposits and encrustation from stones was originally proposed more than 20 years ago by John Asmus who performed pioneering trials of laser cleaning on stone façades in Venice, Cremona and Padua. The opportunity to collect stone samples from these sites allowed us to carry out an original study aimed at evaluating the conservation state of stone surfaces cleaned 10–20 years ago by means of three different techniques: Nd:YAG laser radiation, micron sandblasting and chemical pads. Samples of various stone types, as Istria limestone, Botticino limestone and Nanto sandstone were collected and examined by means of optical and SEM microscopy, FT/IR, and EDAX analyses. The results provided preliminary indications that the state of conservation of stone surfaces previously subjected to laser cleaning is generally better in comparison with those which concurrently underwent mechanical and chemical cleaning.  相似文献   

6.
Black limestone samples from the quarries of Varenna (Lecco, I), Cene (Bergamo, I) and Riva di Solto (Bergamo, I) and widely used in Lombard architecture have been studied in terms of mineralogical, petrographic and chemical properties in order to provide a detailed characterisation and allow an unambiguous determination of their provenance. The inorganic and organic fractions have been separated from each other, and investigated using X-ray powder diffraction, atomic absorption, Hg-porosimetry, high performance liquid chromatography, gas chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The occurrence of specific mineral phases, some binary chemical patterns (Fe/Mn, Zn/Sr, Zn/Co and Na/Cd) and the carbon chain relative molecular masses has proven to be useful markers to characterise unequivocally the materials studied.  相似文献   

7.
This work is focused on the petro-archeometric characterization of the fine pottery production of the archaeological site of Gela (Sicily). Thirty-five samples coming from three Archaic and Hellenistic kilns and five coming from an Hellenistic house, were investigated by means of optical microscopy, XRD and XRF analysis. With the exception of some ceramics which are undoubtedly imported, all the samples have similar petrographic features, but on the basis of chemical composition, we can distinguish two different groups. The presence of two local productions is confirmed by the comparison with locally outcropping sediments and with archaic and modern bricks of sure Geloan production. This result is particularly significant for the definition of reference groups of this wealthy polis that played an important trading role in the Mediterranean area.  相似文献   

8.
Implementation of laser technology in art conservation has resulted in an increased consideration of intervention restoration processes. Skepticism is raised regarding the side effects of interactions that could induce either short- or long-term irreversible physical alterations. Herein, an integrated laser-optic module based on the principles of holographic interferometry (HI) has been developed to study existent structural condition and probable alterations. The experimental procedure involved allows repeatable data acquisition in long-term monitoring. The tested system and methodology overcome a fragmented structural approach imposed in art conservation diagnostics by existing instruments and practices, and a full field response offering a detailed source of information is obtained. The controlled procedures by which interference fringes are formed by laser cleaned surfaces permit their long-term comparison. The results urged studies on the fundamental mechanical behavior of defects. Thus, the high resolution of HI recording was used to study the dynamics of deterioration by detecting the potential of existing defects’ natural propagation, which for the first time is described here. The study can form the basis to distinguish natural from artificially induced alterations. Comparative evaluation during conventional conservation consolidation processes was performed on an early El Greco painting which resulted in a direct evaluation of the restoration action. The results thus far were acquired in laboratory facilities. A custom-developed system was next transported to the museum floor and a significant outcome of on-field holography complementing established structural conservation diagnostics was accomplished.  相似文献   

9.
Potentials and limitations of the near-UV pulsed laser cleaning of parchment (wavelength 308 nm, pulse duration 17 ns) are demonstrated by the application of scanning electron microscopy (SEM), colour metrics and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) at model contamination/pigment/parchment systems. Pigment-binder systems stable and unstable against near-UV laser treatment could be identified. A chemical degradation threshold fluence of a goat parchment model substrate was determined which practically coincided with its ablation threshold fluence. This indicates that the fluence range of destructionless laser cleaning at 308 nm is almost not impaired by chemical modfications below the ablation limit. Nevertheless, spectroscopic diagnostics are necessary to guarantee destructionless cleaning for practical cases where the chemical conversion threshold fluence deviates from the ablation threshold to lower values.  相似文献   

10.
In this paper, we present an application of the infrared thermography to the study of illuminations. In particular, we analyze a 15th century antiphonary from the Biblioteca Angelica of Rome to characterize the conservation state and the structure of the illuminations on the occasion of its planned restoration. We show the results achieved from the stratigraphic investigation of the gilded surface, the parchment substrate and the underdrawing. The obtained information have been, then, used to direct the necessary restoration steps and also to assess the effectiveness of the treatments by a comparative analysis of the thermograms recorded before and after the restoration.  相似文献   

11.
In the present work, an analytical characterization of painted plaster samples coming from ancient buildings dated back to 2nd cent. B.C., located in Licata (Sicily, Southern Italy), has been carried out. The investigation has been performed through different spectroscopic techniques: X-ray fluorescence (XRF) using an handheld energy-dispersive XRF analyzer, scanning electron microscopy equipped with an Energy Dispersive Spectrometry microanalysis detector (SEM-EDS) and Fourier transform infrared absorbance spectroscopy (FT-IR). The main goal is to identify the plaster and pigments material. In particular, the XRF investigation of surfaces is the first step for a preliminary elemental characterization. Then, through SEM-EDS measurements, a quantitative analysis of the chemical composition of the plaster and the pigmenting agents along with eventual components related to deterioration processes has been obtained. Finally, FT-IR absorbance spectra have proven to be a useful tool to investigate the molecular nature of the used materials.  相似文献   

12.
The use of coloured pastes for inlaying marble and limestone wall panels is one of the ornamental techniques that were widely used during the Mamluk period in Egypt (1250–1516 AD). Red and black pastes from Qijmas El-Eshaqe mosque (1482 AD) in Cairo were studied to identify their main components. The study of the samples involved the identification of the pigments, additive materials and organic binding media. The study was performed using various analytical methods such as polarising microscopy (PLM), scanning electron microscopy equipped with energy dispersive X-ray analyser (SEM-EDX), inductively-coupled plasma (ICP-AES), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). These complementary analytical techniques provide precise identification of inorganic and organic substances used in the pastes. The results indicated that the red pigment is mainly obtained from red ochre containing hematite, whereas amorphous carbon (bone black and charcoal) was used to obtain the black colour. Both samples contain calcium sulphate, which was used to give some hardness to the pastes. Beeswax was used as an organic medium in both pastes. The study provides the information required for the conservation of the coloured paste ornaments.  相似文献   

13.
Recent research, concerning the application of high-frequency cold plasma in restoration and preservation of the cultural heritage, has included the objects derived from organic materials, which are highly sensitive to microclimate factors. Historical photographs made on paper base and covered with various emulsions belong to this category of heritage objects, and make the purpose of the present study. Plasma treatment was used to enhance the aesthetic aspect of the photographs by a cleaning treatment involving either physical and/or chemical etching, which did not cause major physicochemical changes on the plasma-treated surface. The photographs before and after plasma treatments were analysed by optical and atomic force microscopy, scanning electron microscopy with energy-dispersive X-ray microanalysis, Fourier transform infrared spectroscopy, colour, gloss and contact angle measurements.  相似文献   

14.
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15.
The present work was one of the first attempts to analyze the conservation status of two ferrotypes, ancient photographic plates realized on a support made of iron. The photographic material was constituted of collodion as binder for the photosensitive silver halides grains. The two ferrotypes studied belonged to a private collection of a family from Durham, UK, and were made at the end of the 19th century. The analytical techniques used for the morphological and physicochemical characterization were noninvasive. The surface morphology was studied by means of optical microscopy (OM) and environmental scanning electron microscopy (ESEM) coupled with an energy dispersive X-rays (EDX) system for the elemental analysis. These techniques, together with microreflectance Fourier transform infrared spectroscopy (μ-FTIR) and contact angle, allowed to obtain information on both the chemical – elemental – composition of the materials constituting the ferrotypes, and the conservation status of these photographic plates. The study showed that the physicochemical diagnostics allowed to characterize the two ferrotypes that, despite their similar age and provenance, showed different conservation status, surface properties, and elemental composition.  相似文献   

16.
Money is an ‘instrument of collective memory’ before it is a means of exchange, a unit of account or a store of value. Money's status as a memory technology is particularly significant in light of the role that information and communication technologies now play in economic transactions. Many of the new channels and infrastructures for payments, such as magnetic cards, mobile phones, the wired Internet, social media platforms, and RFID technologies, record detailed transactional data alongside a range of other identifying data. We now have extremely detailed records of the many ways that money circulates, is transferred and is spent. This paper concerns this previously latent transactional data and how it is currently recorded, monetised, and used to inform action. What has been recorded in and about money at different moments in time and how are these categories breaking down? Who has access to and ownership over this collectively produced record and how is it driving new data practices and business models based on the monetisation and application of monetary records? And how might re-engaging with money's mnemonic status help to foreground a politics and ethics of transactional data?  相似文献   

17.
The use of a scanning electron microscope equipped with a microanalytical system is proposed for characterising ancient mortars. A calculation procedure is presented that allows a determination of the binder and aggregate compositions (including volatile components) from microprobe data collected on the binder, and chemical, mineralogical, petrographical and physical data collected on the mortar bulk sample. The proposed procedure is applied to 11 mortar samples from three historical monuments built in Pisa throughout the Middle Ages. The binder of the analysed samples consists of a carbonate crystalline fraction and an amorphous carbonate-free fraction that makes up from 20 to 60 % by weight of the binder. The aggregate composition, on average, is close to that of the Arno River sands.  相似文献   

18.
In the interdisciplinary domain of conservation science, a critical and selective eye is required in order to allow researchers to choose the most effective combination of analytical techniques for each project and, more importantly, to process and analyze the resulting volume of diverse data. The current essay attempts to combine a more traditional workflow for the examination of painted objects with techniques borrowed from the domain of computer science in order to yield the maximum amount of information and make that added knowledge more accessible to the researcher. The project was approached as a case study, regarding a post-Byzantine icon. Three-dimensional digitization with a laser scanning system, X-ray radiography and optical microscopy were applied for the determination of several structural characteristics of the painted surface and the icon's state of preservation. Multispectral imaging was used for the collection of surface spectral data, which were subsequently processed by means of cluster analysis in a novel approach to map the composition of the painted surface. Finally, micro-X-Ray Fluorescence (μ-XRF) was chosen as the primary source for surface pointwise elemental composition data while Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography coupled with Mass Spectroscopy (GC-MS) provided additional assistance in the characterization of materials based on their molecular structure. A custom platform was developed to address the issue of multilevel visualization and assessment of the data, designed to act as a tool for viewing and combining the acquired information. Via this integrated approach valuable information regarding the icon was revealed, including the verification of a prior conservation attempt and partial overpainting, the recording and quantification of the warping of the wooden panel and, finally, the identification of the constituent materials and their spatial distribution.  相似文献   

19.
The aim of this study is practically to establish a chemical strategy for cleaning soiled deposits and encrustations on archaeological glasses. Investigations were performed on a series of Roman glass samples (Fragments and complete objects) coming from different excavations in northern Jordan. The chemical composition of the glass samples was determined by X-ray fluorescence spectrometer (XRF) analysis technique, whereas X-ray powder diffractometer (XRD) and Energy dispersive X-ray (EDX) methods were used to determine the mineralogical and elemental composition of the soiled deposits and encrustations on the glass surfaces. Furthermore, Scanning Electron Microscopy (SEM) examination and optical assessment were performed before and after cleaning glass. The glass samples were subjected to different cleaning protocols such as Calgon (Sodium hexametaphosphate), ethylenediaminetetraacetic acid (EDTA) at different pH values, citric and tartaric acids and piranha solution (a solution of sulphuric acid and hydrogen peroxide). Sepiolite poultices soaked by chemical agents were the most suitable methods used for applying chemical solutions on the glass surface. It can be concluded that EDTA is generally accepted as the most effective chelating agents recommended for cleaning encrustations on durable glass. It was more effective and safe at neutral pH with low concentrations around 5 to 7%. The calcareous crusts can safely be removed by using a piranha solution. Citric and tartaric acids appeared a moderate efficiency on cleaning weathered and stable glass. Calgon has a tendency to damage corroded and iridescent surfaces, and should be avoided when cleaning weathered glass.  相似文献   

20.
Experimental data concerning an ancient stained window attributed to Nicolò di Pietro Gerini, Carthusian monastery, Galluzzo (Florence), are reported. The chromophores were identified non-invasively in situ by means of a spectro-analyser equipped with optical fibres. The novelty of the method consists in the use of the external solar light as a lighting source so as to increase the signal to noise ratio. Moreover, data on the chemical composition of the glasses and their alteration products, which were obtained from small fragments, are reported. Finally, a hypothesis about the origin of a colour change from blue to purple inside a pane is put forward on the basis of the spectroscopic results.  相似文献   

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