196,353 research outputs found
Characterisation of colourants on a 15th century Armenian manuscript by means of different spectroscopic techniques
No full textThis contribution illustrates the results from the technical study of a 15th century Armenian illuminated manuscript produced at Aghtamar Island (Vaspurakan region, historic Armenia), presently kept in the collection of Matenadaran ancient manuscript museum, in Yerevan. Fifteen fragments taken from different miniatures in the manuscript were analysed by means of UV-Visible diffuse reflectance spectrophotometry with optic fibres (FORS), fluorimetry, Raman spectroscopy, SERS and SEM-EDX. The combination of molecular and elemental techniques allowed the characterisation and identification of colourants used in miniatures; these were carbon, cinnabar, indigo, iron-gall ink, orpiment, red lead, ultramarine blue, vergaut and white lead. A pink dye was assigned to lac dye according to preliminary measurements. The goal was to compare the results with a previously analysed 14th century manuscript coming from the same region: were the same colourants used or not
Glass fragments from the Crypta Balbi in Rome: The composition of eighth-century fragments
No full textEighth-century glass fragments from the Crypta Balbi in Rome were analysed by inductively coupled plasma emission spectroscopy. The samples included fragments of artefacts as well as ingots of raw glass and wasters. All the fragments proved to be soda-lime glasses. Manganese-to-iron atomic ratios are highly variable and determine the colour of a large number of samples. Fairly high copper contents, generally associated with relatively high amounts of antimony and lead, were detected in some green and blue-green samples: this suggests recycling of glass in the form of opaque mosaic tesserae. All three elements are higher in eighth-century than in previously analysed seventh-century fragments. This may indicate greater recourse to recycled glass, related to a reduction in trade exchanges in the Mediterranean
Comparison Between Microwave and Conventional Heating Procedures in Tessier’s Extractions of Calcium, Copper, Iron and Manganese in a Lagoon Sediment
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Surface enhanced Raman scattering for the analysis of red lake pigments in painting layers mounted in cross sections
No full textCross 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
A protocol for non-invasive analysis of miniature paintings
No full textThe characterisation of palettes used in medieval manuscript illumination is an important task from the historical-artistic point of view, but a hard one from the scientific point of view: miniatures cannot be sampled, it is unsuitable to use techniques
operating in contact (i.e. IR in ATR mode) and to perform long-lasting analytical sessions, due to the stress that can be inferred to manuscripts. For these reasons it is necessary to use analytical techniques either non-invasive and fast; moreover,
in most of cases it is necessary to work in situ with portable instruments. Among available techniques working in portable versions, Raman spectroscopy is the most informative, due to its diagnostic power; it requires, though, long time of analysis. XRF spectrometry is a powerful alternative but, being an elemental technique, in some cases it does not yield accurate results. UV-visible-NIR spectrophotometry in reflectance mode with fibre optics (FORS) can be promising as preliminary technique with some apparent limits. In this work a protocol of analysis is proposed for characterisation of miniature paintings on manuscripts in non-invasive way, using only portable techniques and performing in situ analysis. The protocol allows identification of colorants by successive application of complementary techniques, exploiting the advantages of each technique. First of all a palette with several pigments, dyes and lakes on parchment
has been prepared with colorants that were in use in Middle Ages; paints have been prepared in gum Arabic and in egg white, according to ancient recipes described in medieval textbooks such as De arte illuminandi by anonymous, Compositiones ad tingenda musiva by anonymous and Il libro dell’arte by Cennino Cennini. This palette is the base on which to build a database of spectroscopic analysis, reproducing a
situation similar to the one present on manuscripts. It is important, therefore, to stress out the fact that spectra collected from this palette are more reliable that spectra obtained from analysis of colorants in powder. Protocol is started with an overall
investigation with FORS, collecting spectra from all painted areas of the manuscript and comparing them with the database. This allows to identify almost 60-70 % of the colorants present. Then visual inspection of the paintings is performed with a digital camera connected with a 10-80x microscope, in order to have a clear image of areas that show uncertain FORS spectra, i.e. mixtures of pigments, altered paints, etc. Then XRF spectrometry is performed in order to characterise metal pigments (i.e. gold, silver and copper pigments), to verify the presence of overlapping layers, to identify mordants for dyes and lakes and to identify contaminants in pigments yielding information useful to study the provenance of raw materials for colorants. At this stage almost 90% of colorants can be identified. Finally Raman spectroscopy is used for the most uncertain cases. After application of these techniques a wealth of information is obtained, causing little or no stress at all to the manuscripts under analysis
On the hierarchical use of colourants in a 15th century book of hours
No full textAn illuminated Book of Hours (in use in Chalon-sur-Saône) currently owned by the Museo Civico di Arte Antica and displayed in the prestigious Palazzo Madama in Torino (Italy) was investigated by means of optical microscopy, fibre optic reflectance spectroscopy, fibre optic molecular fluorimetry, X-ray fluorescence spectrometry and Raman spectroscopy. The aim of the scientific survey was to expand the knowledge of the manuscript itself and on the materials and techniques employed by Antoine the Lonhy, the versatile itinerant artist who decorated the book in the 15th century. The focus was to reveal the original colourants and to investigate the pigments used in rough retouches which were visible in some of the miniatures. The investigation was carried out in situ by portable instruments according to a non-invasive analytical sequence previously developed. It was evident that the use of different pigments by the master was ruled, at least partially, by a hierarchical scheme in which more precious materials were linked to the most important characters or details in the painted scene
Compositional and micro-morphological characterisation of red colourants in archaeological textiles from pharaonic Egypt
No full textWhen the imagination conjures up an image of an Egyptian mummy, it is normally one of a human body wrapped with undyed linen bandages. However, the reality was much more colourful, as shown by the set of red mummy shrouds and textile fragments from Pharaonic Egypt considered in this work. The textiles were subjected to scientific investigation with the main aim of shedding light on the sources of red colour and on the possible reasons for the different levels of colour fading. The red colourants were investigated using various non-invasive and micro-invasive approaches. The results pointed towards the presence of three sources of red colour, which, in increasing order of lightfastness, are safflower (Carthamus tinctorius), madder (Rubia spp.), and red ochre. Micro-morphological observations and elemental analyses also enabled some hypotheses to be formulated regarding the application of these colourants to the textiles. The results not only deepen our knowledge of dyeing technologies in ancient Egypt and shed new light on the function of red shrouds and textiles as part of the funerary practices of Pharaonic Egypt, but are also essential in planning the display and future preservation of these mummies and their associated textiles
Identification of dyes in Persian manuscripts
No full textPersian manuscripts are among the most beautiful artistic productions in the field of miniature painting. Knowledge of the colorants used by Persian artists, however, is not as thorough as the knowledge of pictorial materials used in Western manuscripts. It is only recently that advanced instrumental analytical techniques have been applied to the investigation of colorants in Persian miniatures. Nevertheless, very little diagnostic information is available on the use of organic colorants, so our understanding of this aspect relies mostly on bibliographic sources. This paper provides an overview of the scarce literature on scientific analyses of organic colorants in Persian manuscripts and offers further examples of their use by reporting the results of non-invasive analyses performed on some books held in northern Italian libraries and museums. The occurrence of two types of coccid dyes (but no evidence for the use of madder), Indian yellow, safflower red, a tannin-like dye and indigo was ascertained by in situ application of portable techniques such as UV-visible diffuse reflectance
spectrophotometry and spectrofluorimetry
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