A Nanofocused Light on Stradivari Violins: Infrared s-SNOM Reveals New Clues Behind Craftsmanship Mastery.

It is well-known that all the phases of the manufacturing influence the extraordinary aesthetic and acoustic features of Stradivari's instruments. However, these masterpieces still keep some of their secrets hidden by the lack of documentary evidence. In particular, there is not a general consensus on the use of a protein-based ground coating directly spread on the wood surface by the Cremonese Master. The present work demonstrates that infrared scattering-type scanning near-fields optical microscopy (s-SNOM) may provide unprecedented information on very complex cross-sectioned microsamples collected from two of Stradivari's violins, nanoresolved chemical sensitivity being the turning point for detecting minute traces of a specific compound, namely proteins, hidden by the matrix when macro or micro sampling approaches are exploited. This nanoresolved chemical-sensitive technique contributed new and robust evidence to the long-debated question about the use of proteinaceous materials by Stradivari.

Reflection FTIR spectroscopy for the study of historical bowed string instruments: Invasive and non-invasive approaches.

A micro-sample detached from a historical bowed string instrument represents a valuable record of the materials used by the great Masters of violin-making art. It allows researchers to collect a wealth of information and to disclose - at least partially - their procedures for finishing and varnishing. In the present work, a set of four cross-sectioned micro-samples - collected from well-preserved bowed string instruments made by Antonio Stradivari and Lorenzo Storioni - are investigated by Synchrotron Radiation (SR) FTIR micro-spectroscopy in reflection mode. SR-FTIR spectra are discussed both as point analysis and as univariate and multivariate chemical maps. The same cross-sections are also investigated by optical microscopy under UV light and SEM-EDX. Moreover, data obtained directly from the musical instruments by a non-invasive approach employing a portable reflection FTIR spectrometer are also considered. FTIR investigation of the cross-sections is a challenging task for such brittle and complex layered micro-samples. Nevertheless, the high intensity of the analytical SR beam used in reflection geometry allowed us to obtain informative FTIR spectra and to fully preserve the integrity of the samples. Both the non-invasive and the micro-invasive reflection FTIR approaches can reveal the materials spread on the wood surface to finish the musical instruments. The fingerprint of Lorenzo Storioni's production around 1790 emerged from the study of the cross-sectioned samples, definitely different from the technique of Stradivari.

Compositional and Micro-Morphological Characterisation of Red Colourants in Archaeological Textiles from Pharaonic Egypt.

When 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.

Technology of production of red figure pottery from Attic and southern Italian workshops.

Samples from Greek figure vases were investigated by scanning electron microscopy coupled with energy dispersive X-ray analysis, X-ray diffraction, thermomechanical analysis and reflectance spectroscopy to achieve a technological characterisation. The vases, dating from the end of the sixth to the fourth century BC, had been excavated at Locri Epizephiri (Calabria, Italy) and attributed to Attic or local workshops, respectively. Information on the morphology of black slip areas and firing temperatures was compared with that previously obtained for Attic and local black gloss pottery from the same site; results show that the peculiar technique required for the production of black slips was mastered by both Attic and local potters and employed for monochrome and figured products. The black coating is usually well vitrified and 15- to 20-microm thick; the evaluated maximum firing temperature is around 900 degrees C, while a temperature lower than 800 degrees C is generally estimated for ceramic body re-oxidation.

Colourants and opacifiers in seventh and eighth century glass investigated by spectroscopic techniques.

Glass fragments dating from the seventh and eighth century AD were excavated in the Crypta Balbi in Rome. They were studied to detect agents involved in colour development and opacification. Reflectance spectra recorded on powdered samples revealed the contribution of Fe(II), Fe(III), Mn(III), Cu(II), and Co(II) ions in determining colour hues. The effect of the Mn/Fe atomic ratio on glass colour is discussed. It is apparent that medieval glassmakers in Italy could obtain a wide range of colours by exploiting the presence of iron and manganese as contaminants of sand and flux and controlling the amount of oxygen let into the furnace. X-ray diffraction and scanning electron microscopy coupled with energy-dispersive X-ray analysis were used to study opaque fragments. The presence of calcium antimonate was detected in white, blue, and blue-green fragments, and elemental copper was detected in a red glass.