Trasmission and Reflection (ATR)Far-Infrared Spectroscopy Applied in the Analysis of Cultural Heritage Materials

FIR spectroscopy is an alternative way of collecting spectra of many inorganic pigments and corrosion products found on art objects, which is not normally observed in the MIR region. Most FIR spectra are traditionally collected in transmission mode but as a real novelty it is now also possible to record FIR spectra in ATR (Attenuated Total Reflectance) mode. In FIR transmission we employ polyethylene (PE) for preparation of pellets by embedding the sample in PE. Unfortunately, the preparation requires heating of the PE in order to produces at transparent pellet. This will affect compounds with low melting points, especially those with structurally incorporated water. Another option in FIR transmission is the use of thin films. We test the use of polyethylene thin film (PETF), both commercial and laboratory-made PETF. ATR collection of samples is possible in both the MIR and FIR region on solid, powdery or liquid samples. Changing from the MIR to the FIR region is easy as it simply requires the change of detector and beamsplitter (which can be performed within a few minutes). No preparation of the sample is necessary, which is a huge advantage over the PE transmission method. The most obvious difference, when comparing transmission with ATR, is the distortion of band shape (which appears asymmetrical in the lower wavenumber region) and intensity differences. However, the biggest difference can be the shift of strong absorbing bands moving to lower wavenumbers in ATR mode. The sometimes huge band shift necessitates the collection of standard library spectra in both FIR transmission and ATR modes, provided these two methods of collecting are to be employed for analyses of unknown samples. Standard samples of 150 pigment and corrosion compounds are thus collected in both FIR transmission and ATR mode in order to build up a digital library of spectra for comparison with unknown samples. XRD, XRF and Raman spectroscopy assists us in confirming the purity or impurity of our standard samples. 24 didactic test tables, with known pigment and binder painted on the surface of a limestone tablet, are used for testing the established library and different ways of collecting in ATR and transmission mode. In ATR, micro samples are scratched from the surface and examined in both the MIR and FIR region. Additionally, direct surface contact of the didactic tablets with the ATR crystal are tested together with water enhanced surface contact. In FIR transmission we compare the powder from our test tablet on the laboratory PETF and embedded in PE. We also compare the PE pellets collected using a 4x beam condenser, focusing the IR beam area from 8 mm to 2 mm. A few samples collected from a mural painting in a Nepalese temple, corrosion products collected from archaeological Chinese bronze objects and samples from a mural paintings in an Italian abbey, are examined by ATR or transmission spectroscopy.

A Multilevel Model with Time Series Components for the Analysis of Tribal Art Prices

In the present work we perform an econometric analysis of the Tribal art market. To this aim, we use a unique and original database that includes information on Tribal art market auctions worldwide from 1998 to 2011. In Literature, art prices are modelled through the hedonic regression model, a classic fixed-effect model. The main drawback of the hedonic approach is the large number of parameters, since, in general, art data include many categorical variables. In this work, we propose a multilevel model for the analysis of Tribal art prices that takes into account the influence of time on artwork prices. In fact, it is natural to assume that time exerts an influence over the price dynamics in various ways. Nevertheless, since the set of objects change at every auction date, we do not have repeated measurements of the same items over time. Hence, the dataset does not constitute a proper panel; rather, it has a two-level structure in that items, level-1 units, are grouped in time points, level-2 units. The main theoretical contribution is the extension of classical multilevel models to cope with the case described above. In particular, we introduce a model with time dependent random effects at the second level. We propose a novel specification of the model, derive the maximum likelihood estimators and implement them through the E-M algorithm. We test the finite sample properties of the estimators and the validity of the own-written R-code by means of a simulation study. Finally, we show that the new model improves considerably the fit of the Tribal art data with respect to both the hedonic regression model and the classic multilevel model.

Salomé et Jean Baptiste. Réinvestissements symboliques et récritures d'un mythe dans la littérature et dans l'art (1870-1914)

La publication de nombreuses œuvres, à la fois littéraires et picturales, entre 1870 et 1914, inspirées par l’épisode biblique du meurtre de Jean Baptiste par Salomé, s’inscrit dans une crise qui touche à cette époque, en Europe, aussi bien le sujet que la notion de représentation. Le mythe de Salomé permet de poursuivre une réflexion de nature littéraire, historique et esthétique concernant le processus d’autonomisation de l’art. À partir des sources bibliques et antiques, dans lesquelles Salomé et Jean Baptiste incarnent respectivement le monde païen en conflit avec le monde chrétien, ces deux personnages font graduellement leur entrée dans l’univers de la fiction. Ils sont au cœur de la transition d’une lecture transcendante — reliée particulièrement à la tradition catholique — de l’épisode tragique qui les unit, à une lecture immanente qui en fait deux instances purement esthétiques. La danseuse et le dernier des prophètes émergent dans la littérature et dans l’art occidentaux comme deux pôles symboliques, liés l’un à l’autre par différents types de relation, susceptibles d’être librement réinvestis par de nouvelles significations et à l’écart des conventions. Si, dans la première partie du XIXe siècle, Salomé et Jean Baptiste sont encore liés à leur sens orthodoxe, au tournant du siècle ils finissent par s’autonomiser de l’Écriture et donnent lieu à de multiples récritures et à des adaptations inattendues. Celles-ci ressortissent alors moins du blasphème à proprement parler que d’un témoignage emblématique d’une transformation du rapport que l’artiste entretient avec son œuvre. Celui-ci, en s’identifiant avec le prophète décollé, se mesure à l’œuvre d’art, qui est incarnée par Salomé. La relation entre Salomé et Jean Baptiste, dans ces diverses représentations, exprime et reflète le moment où art et littérature se reconnaissent comme fictions.