1,721,409 research outputs found
Un ossuario fittile a campana del Museo Archeologico di Milano (con Appendice di S. Bruni)
No full textLe ceneri di l(ari)s ane erano contenute in un vaso di forma troncoconica con le pareti rastremate verso l’alto. Il cinerario, privo di contesto è conservato nelle Civiche Raccolte Archeologiche e Numismatiche di Mlano. Trova numerosi confronti a Chiusi dove costituisce una novità tarda: se da un lato la forma non sembra avere precisi precedenti, dall’altro la decorazione può averne solo vaghi e non direttamente confrontabili, soprattutto per il rapporto che si stabilisce con la tettonica del vaso.
Lo studio dei confronti, condotto in parallelo da un lato sulla forma a campana e dall’altro sulla decorazione policroma su fondo bianco, a ghirlande e bende, consente tuttavia di individuare ascendenti compositi, oltre che nella grande pittura parietale, anche nel repertorio ceramico di ambito magno greco (ceramica figurata apula, ceramiche dello stile di Gnathia) e di ambito egeo (ceramiche West Slope, hydrie di Hadra).
Le analisi chimiche condotte sulla tecnica pittorica del cinerario in esame, coordinate da Silvia Bruni, danno corpo alla tesi di un’operazione successiva alla cottura, confermando così l’accostamento usuale in letteratura con la tecnica di decorazione delle pareti delle tombe, che venivano intonacate per essere dipinte a fresco. Sulla base delle considerazioni avanzate sugli ascendenti sia formali sia stilistici che conducono nella medesima direzione la tesi avanzata è che nell’insieme il vaso alluda alla sfera semantica del passaggio alla condizione ultraterrena percepibile nelle tombe tarquiniesi dipinte.
Lo studio degli ascendenti di forma e decorazione del cinerario può infatti procedere da un dato sicuro, al fine di comprendere a quali tradizioni si ispirasse l’oggetto e in che modo esse fossero accolte nella tradizione locale della città di Chiusi
Gilt stuccoes of the italian baroque
No full textC. Colombo, L. Toniolo, S. Bruni, P. Fermo, A. Casoli, G. Palla, C. L. Bianchi, Gilt stuccoes of the italian baroque. Studies in Conservation, 43, 1998, 201-208
Molecular spectroscopy for the in-situ investigation of cultural heritage materials
No full textIn 1815, the British scientist Sir Humphry Davy , discoverer of chemical elements such as sodium, potassium and calcium, published in the Philosophical Transactions of the Royal Society of London an essay “on the colours used in painting by the ancients”, after analyzing by wet chemistry methods pigments drawn from wall paintings of imperial Rome. Since then, the need to identify cultural heritage materials was maintained and even increased, not only for sake of knowledge but also as a basis for conservation, possibly restoration and even authentication of works of art. At the same time, the range of objects to be analyzed has enlarged to include, besides paintings, many other expressions of art and craftsmanship of the past. Moreover, in some cases not only original materials but also their possible alteration products need to be recognized. In the meanwhile, the development of a wide range of synthetic materials used in contemporary art has made the task of their identification even more challenging.
On the side of analytical techniques, the evolution towards instrumental methods, especially spectroscopic ones, opened the possibility of increasing information while reducing the amount of sample required, till the development of completely non-invasive techniques.
In this context, given the complexity of the analytical problem, the use of molecular spectroscopy has a meaningful role, especially if the highly compound-specific vibrational spectroscopies are considered. The potentiality of in-situ non-destructive infrared and micro-Raman analyses by means of compact, movable equipment will be described for different kinds of artefacts, together with the combined use of Raman instrumentation for micro-fluorimetric measurements
An evaluation of the effectiveness of SERS in the identification of textile dyes in real archaeological and historical samples
No full textIn the last few years the application of surface-enhanced Raman spectroscopy to the identification of historical dyes has significantly developed from the point of view of analytical protocols, aiming to reduce the need for sample pre-treatment, the required amount of sample [Brosseau et al. 2011] or even to completely avoid sampling [Leona et al. 2011]. These aspects of the evolution of the technique were extensively reported and reviewed in the literature.
Whenever an analytical chemist is involved in the solution of a problem concerning the cultural heritage, he has to deal with two different issues: the development of suitable methods and the need to give precise answers to the questions of archaeologists and art historians. At the present stage of improvement of the SERS techique for the identification of dyes, it is therefore useful to evaluate its capability in recognising such substances, especially those used for textile dyeing, in a field where other analytical methods, i.e. those based on high-performance liquid chromatography (HPLC), are still most commonly and routinously used by specialised laboratories.
Examples concerning the possibility of recognising by SERS dyes used in archaeological and historical samples from particular geographical areas or in the decoration of unusual textile artefacts will be discussed, with special attention to those cases where identification is made more difficult by the need of a widened database or by the use of dyes in mixtures or even by degradation effects
La necropoli di San Chierico di Bolgare : le analisi chimiche su un frammento di cuoio dal fodero del Langsax
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Resine profumate, colori pregiati e fili d'oro nei sepolcri ambrosiani. La storia di un'analisi, la cronaca di un evento.
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