Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of cerussite PbCO and hydrocerussite Pb(CO)(OH)). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.

Based on a retrospective study of 179 MRI records covering four populations (patients presenting with impingement without known injury (n = 90), post-traumatic shoulder pain (n = 28), instability or dislocation (n = 36) and controls (n = 25)), morphologic criteria are suggested to define presumedly normal arches and arches compatible with subacromial impingement. The subacromial arch is presumed normal or without impingement if the sagittal and frontal views show it to be parallel to the humeral head, and/or if there is a fatty layer interposed between the arch and the supraspinatus m. The arch is presumed "aggressive" or actually capable of giving rise to impingement if, in either the sagittal or frontal view, there is a zone of narrowing of the subacromial passage with an impression of the arch on the supraspinatus tendon or tendinous thinning at this level or just lateral to this narrowed zone. Based on these criteria, study of the 179 MRI records demonstrated a significant difference of distribution of the arches in the four populations. "Aggressive" arches were found in 45.5% of patients with impingement, 25% of patients with posttraumatic pain, 8.9% of patients with an acute or recurrent dislocation and 12% of controls. Conversely, a presumedly normal arch was found in 56% of the controls, 55% of patients with dislocation, 25% of posttraumatic painful shoulders and only 5.5% of patients with clinical impingement. Subacromial impingement may be due to the type 3 acromial dysplasia described by Bigliani or to a thickening of the coracoacromial ligament at its acromial attachment. This study was supplemented by 15 anatomic dissections which confirmed the regularity of attachment of the coracoacromial ligament at the inferior aspect of the acromion along its lateral border.

Scanning XRF is a powerful elemental imaging technique introduced at the synchrotron that has recently been transposed to laboratory. The growing interest in this technique stems from its ability to collect images reflecting pigment distribution within large areas on artworks by means of their elemental signature. In that sense, scanning XRF appears highly complementary to standard imaging techniques (Visible, UV, IR photography and X-ray radiography). The versatile XRF scanner presented here has been designed and built at the C2RMF in response to specific constraints: transportability, cost-effectiveness and ability to scan large areas within a single working day. The instrument is based on a standard X-ray generator with submillimetre collimated beam and a SDD-based spectrometer to collected X-ray spectra. The instrument head is scanned in front of the painting by means of motorised movements to cover an area up to 300 9 300 mm 2 with a resolution of 0.5 mm (600 9 600 pixels). The 15-kg head is mounted on a stable photo stand for rapid positioning on paintworks and maintains a free side-access for safety; it can also be attached to a lighter tripod for field measurements. Alignment is achieved with a laser pointer and a micro-camera. With a scanning speed of 5 mm/s and 0.1 s/point, elemental maps are collected in 10 h, i.e. a working day. The X-ray spectra of all pixels are rapidly processed using an open source program to derive elemental maps. To illustrate the capabilities of this instrument, this contribution presents the results obtained on the Belle Ferronnière painted by Leonardo da Vinci (1452-1519) and conserved in the Musée du Louvre, prior to its restoration at the C2RMF.

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Introduction: Giotto (1266-1337) and his workshop realized c. 1315 the large Crucifix now in the Louvre Museum. The conservation of this masterpiece in 2010-2013 in the C2RMF studios gave the opportunity for a comprehensive investigation of the execution technique through a characterization of the paint layers. The first examinations revealed an original gilding and decoration surrounding the Christ which was repainted during the 19 th C., raising the question of the original decoration appearance. Results: The original decoration still present underneath was unveiled. The different imaging analytical techniques applied brought complementary results allowing us to reconstruct the original decoration. Elemental images of selected areas on the Crucifix were obtained using bi-dimensional X-ray fluorescence imaging technique (2D-XRF) with a prototype XRF spectrometer mounted on a motorized X-Y system. The head of the instrument was moved over a 150 x150 mm

Leonardo da Vinci (1452–1519) is a key artistic and scientific figure of the Renaissance. He is renowned for his science of art, taking advantage of his acute observations of nature to achieve striking pictorial results. This study describes the analysis of an exceptional sample from one of Leonardo’s final masterpieces: The Virgin and Child with St. Anne (Musée du Louvre, Paris, France). The sample was analyzed at the microscale by synchrotron-based hyperspectral photoluminescence imaging and high-angular X-ray diffraction. The results demonstrate Leonardo’s use of two subtypes of lead white pigment, thus revealing how he must have possessed a precise knowledge of his materials; carefully selecting them according to the aesthetical results he aimed at achieving in each painting. This work provides insights on how Leonardo obtained these grades of pigment and proposes new clues regarding the optical and/or working properties he may have tried to achieve.

The blanching of easel paintings can affect the varnish layer and also the paint layer with a blurring effect. The understanding of the physicochemical and optical phenomena involved in the whitening process remains an important challenge for the painting conservation. A set of ca. 50 microsamples from French, Flemish, and Italian blanched oil paintings, from sixteenth to nineteenth century, have been collected for in deep investigations. In parallel, the reproduction of the alteration was achieved by preparing some paint layers according to historical treatises and altering them in a climatic chamber in a humid environment or directly by immersing in ultrapure water. The observation of raw samples with a field-emission gun scanning electron microscope revealed for the first time that the altered layers have an unexpected highly porous structure with a pore size ranging from ca. 40 nm to 2 lm. The formation mechanism of these pores should mostly be physical as the supplementary analyses (Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry) do not reveal any noticeable molecular modification. Considering the tiny size of the pores, the alteration can be explained by the Rayleigh or Mie light scattering.

Historical paintings with important iconographical changes represent an analytical challenge. Considering the case study of a fifteenth-century French painting studied during its restoration, the efficiency of a combined noninvasive approach of two-dimensional scanning macro-X-ray fluorescence imaging (MA-XRF) and a laboratory-based depth-resolved confocal micro-X-ray fluorescence (CXRF) is discussed. Large chemical maps of several elements were obtained by MA-XRF, enabling the identification of zones of interest representing changes in the painting composition. In these areas, depth profiles were measured with CXRF, allowing to evidence overlaying paint layers. The advantages of this technique are that it can give direct information on the stratigraphy of paint layers in a nondestructive way and can reduce the sampling needed, as well as increase the locations analyzed (in our study twenty-two depth-resolved scans). These results complement information obtained by scanning electron microscopy coupled with an energy-dispersive X-ray analyzing system (SEM–EDX) on three cross-sectional samples taken in the areas of interest. Additionally, the three cross sections of the painting were studied by CXRF lateral scans (y) in order to evaluate the efficiency of the CXRF analyses against SEM–EDX. The study shows the benefits of the combination of MA-XRF and CXRF for analyzing painting compositions, as such a high number of cross sections would have been impossible to sample. From an art-historical and conservation perspective, this combined study provides an understanding of the original painting’s paint sequence and its later retouches, helping to make informed conservation treatment decisions. Graphic Abstract