In-situ technical study of modern paintings - Part 2: Imaging and spectroscopic analysis of zinc white in paintings from 1889 to 1940 by Alessandro Milesi (1856-1945).
We present a multi-analytical in situ non-invasive study of a series of emblematic paintings by Alessandro Milesi (1856-1945) from the collection of the International Gallery of Modern Art Ca' Pesaro in Venice. Eight paintings dated from 1897 to 1910 were studied with imaging and spectroscopic techniques. White pigments were characterized by a combination of X-ray fluorescence spectroscopy which traced the presence of zinc-based pigments in Milesi's paintings, Raman Spectroscopy, Laser Induced Fluorescence (LIF) Spectroscopy and Time-resolved Luminescence Imaging. Time-resolved analysis of luminescence emissions revealed the nanosecond emission from organic compounds and the slower emission from the luminescent inorganic pigment Zinc Oxide that varied between 1.1 and 1.6 microseconds. In this work, data regarding the distribution of luminescent pigments was acquired with a time-gated imaging detector. Furthermore, differences in emission decay kinetics recorded from different paintings can be ascribed to different paint formulations or origins of the Zinc white in paint.
Investigating counterfeiting of an artwork by XRF, SEM-EDS, FTIR and synchrotron radiation induced MA-XRF at LNLS-BRAZIL.
In this work, a painting suspected of counterfeiting was analyzed using the synchrotron-based scanning macro X-ray fluorescence (MA-XRF) technique. The canvas has erasures including a signature erasure; however, some visible numbers indicate that the artwork may be from the 17th century. Through the studies' elemental maps, Cl-K and Ca-K were observed, which allowed us to reconstruct the signature present in the painting. Elemental maps of Ba-K, Ti-K, Fe-K, Zn-K, and Pb-K were also obtained from the painting, which made possible to visualize how the pigments based on these elements were used in the creative composition of the painting. In addition to the signature region, a region of the painting with dimensions of approximately 120 mm × 120 mm was investigated by synchrotron radiation induced MA-XRF, while keeping a high spatial resolution and elemental sensitivity. The measurements were carried out at the D09B micro-XRF beamline of the Brazilian Synchrotron Light Laboratory (LNLS), part of the Brazilian Center of Research in Energy and Materials, in Campinas Brazil. The painting was also investigated by SEM-EDS, and FTIR techniques. Those results, in addition to the supporting elemental maps, allowed additional information to be obtained, such as the binders used on the painting.
Synthesis of β-FeSi2 nanowires by using silicon nanowire templates
Si nanowires templates were grown by a Cu-catalyzed vapor–liquid–solid process and used for the preparation of β-FeSi2 nanowires on a Si substrate. The silicon nanowires were transformed into β-FeSi2 nanowires by annealing with additional source material containing FeCl2 and Si powder. In contrast to uniform Si nanowire templates along the direction, the synthesized nanowires were deformed irregularly. The electron diffraction pattern of the nanowires synthesized from the template corresponded to that of single-crystalline β-FeSi2 and the longitudinal direction of the nanowire was along the direction. The energy dispersive X-ray fluorescence analysis confirmed that the nanowire contained Fe and Si in an atomic ratio of approximately 1:2. The results confirmed that β-FeSi2 nanowires on a Si substrate were synthesized from the Si nanowire templates.Si nanowires templates were grown by a Cu-catalyzed vapor–liquid–solid process and used for the preparation of β-FeSi2 nanowires on a Si substrate. The silicon nanowires were transformed into β-FeSi2 nanowires by annealing with additional source material containing FeCl2 and Si powder. In contrast to uniform Si nanowire templates along the direction, the synthesized nanowires were deformed irregularly. The electron diffraction pattern of the nanowires synthesized from the template corresponded to that of single-crystalline β-FeSi2 and the longitudinal direction of the nanowire was along the direction. The energy dispersive X-ray fluorescence analysis confirmed that the nanowire contained Fe and Si in an atomic ratio of approximately 1:2. The results confirmed that β-FeSi2 nanowires on a Si substrate were synthesized from the Si nanowire templates.