“Ecce Homo” by Antonello da Messina, from non-invasive investigations to data fusion and dissemination

Abstract

Scientific investigations of artworks are crucial in terms of preservation since they provide a measurable evaluation of the materials and the state of conservation. This is the case of Antonello da Messina’s painting “Ecce Homo”: its delicate state of conservation, with the need for constant monitoring, required a broad and in-depth diagnostic campaign to support the restorers. The project was carried out entirely in situ using non-invasive cutting-edge techniques and proposes a multimodal and data-centric approach, integrating 3D and 2D methodologies. The surface irregularities and the support were analysed with a structured-light 3D scanner and X-ray tomography. The painting materials were investigated with X-ray fluorescence scanning (MA-XRF) and reflectance hyperspectral imaging (HSI). Primarily, the data were jointly used for a scientific scope and provided new knowledge of the painting in terms of materials and painting techniques. In addition, two web-based interactive platforms were developed: one to provide restorers and experts with a new perspective of the hidden geometries of the painting, and the other targeted at the general public for dissemination purposes. The results of the Ecce Homo scientific analysis were exhibited, using a touch-screen interface, and developed for different user levels, from adults to kids.

A high-resolution photogrammetric workflow based on focus stacking for the 3D modeling of small Aegean inscriptions

“…For example, it is well known that structured-light scanners have problems to model shiny and dark objects, such as some of the stone seals analyzed in this study. Finally, most of the metrology 3D scanners are unable to capture colour information [10] and, when available, their texture restitution is not comparable to that of photogrammetry [59], whose high quality texture allows for an in-depth documentation of the artifacts and becomes a key factor whenever the signs are lightly sketched on their surface. For all these reasons, photogrammetry is the optimal solution for the purposes of closely analyzing, correctly reading, and transcribing the small Aegean inscriptions considered here.…”

X-ray Tomography Unveils the Construction Technique of Un-Montu’s Egyptian Coffin (Early 26th Dynasty)

“…X-ray computed tomography is a non-invasive and non-destructive 3D imaging technique capable of revealing crucial information about the manufacturing and assembly techniques of complex objects, such as the Un-Montu coffin. The CT technique investigates the entire volume of an artefact, providing scholars and restorers with knowledge of inner hidden details such as joints and dowels [20,21,29], the presence of different materials [10,30], the construction technique [22,31,32], or the casting process [33,34], and helps to elucidate possible restoration treatments and preservation conditions [10,35,36].…”

“…This is the case in multispectral imaging techniques that give a broad picture of the artefact [1], revealing underdrawings [2]; restored surfaces; and, in some cases, the nature of the pigments [3,4]. The combination of these techniques with other investigations, such as XRF [5,6] and SEM-EDS for the elemental analysis of pigments [7], and FT-IR and Raman spectroscopy for the study of organic components [8,9], make it possible to identify constituent materials without the need for sampling [10,11]. Moreover, emerging techniques such as THz imaging [12][13][14] allow for non-invasive investigation of the external stratigraphy of the objects.…”

Fifteenth century Florentine mural investigated in situ with VNIR Hyperspectral Imaging and NIR Photography supports interpretation as a bloodletting scene

“…Non-invasivity is always a prerequisite, and often a mandatory requirement. Recent research has demonstrated the effectiveness of multi-modal imaging for non-invasive inspection of the entire painting surface and its hidden features by combining advanced imaging techniques, such as Reflectance Imaging Spectroscopy in the Visible, Near-Infrared and Short-wave Infrared (VNIR-SWIR) ranges and Macro-X-rays Fluorescence (MA-XRF) 6 , 7 . Nevertheless, these methodologies use high-precision scanning devices and cumbersome instrumentation which usually operate at close range from the targets and require controlled set-ups 8 .…”