Examination of historical paintings by state-of-the-art hyperspectral imaging methods: from scanning infra-red spectroscopy to computed X-ray laminography

Abstract

The development of advanced methods for non-destructive selective imaging of painted works of art at the macroscopic level based on radiation in the X-ray and infrared range of the electromagnetic spectrum are concisely reviewed. Such methods allow to either record depth-selective, element-selective or species-selective images of entire paintings. Camera-based 'full field' methods (that record the image data in parallel) can be discerned next to scanning methods (that build up distributions in a sequential manner by scanning a beam of radiation over the surface of an artefact). Six methods are discussed: on the one hand, macroscopic X-ray fluorescence and X-ray diffraction imaging and X-ray laminography and on the other hand macroscopic Mid and Near Infrared hyper-and full spectral imaging and Optical Coherence Tomography. These methods can be considered to be improved versions of the well-established imaging methods employed worldwide for examination of paintings, i.e., X-ray radiography and Infrared reflectography. Possibilities and limitations of these new imaging techniques are outlined.

Separating two painting campaigns in Saul and David, attributed to Rembrandt, using macroscale reflectance and XRF imaging spectroscopies and microscale paint analysis

“…While broadband infrared reflectance imaging (i.e. infrared reflectography) has been widely used for decades to detect the presence of underdrawings or to better understand pentimenti, diffuse reflectance imaging spectroscopy (RIS) and XRF imaging spectroscopy (MA-XRF) have more recently been used to chemically identify and map artists' materials [12][13][14][15][16][17][18] and to visualize earlier painted compositions hidden below the surface [19][20][21][22][23]. Findings of this type may result in re-thinking the art historical understanding of the development of a work of art.…”

Hidden library: visualizing fragments of medieval manuscripts in early-modern bookbindings with mobile macro-XRF scanner

“…It is a non-destructive technique that combines elemental analysis with spatial information, resulting in macro-scale elemental distribution maps. Even though MA-XRF has proved to be very valuable for (technical) art historians and art conservators, its possibilities have not been explored yet in the field of book history [4,5]. We propose MA-XRF as an excellent technique to investigate hidden fragments in bookbindings, because of the following reasons.…”

Non-invasive sub-surface analysis of the male portrait underlying the Titian’s Studio Ecce Homo

“…Nonetheless, apart from the use of radioactive sources, NAAR's significant disadvantage is the absence of portable devices requiring transportation of the analysed paintings to the dedicated laboratory. Providing additional research tools to address the challenges presented in the study of paintings hidden under later pictorial compositions, the scanner X-ray fluorescence (XRF) technique has the potential to not only reveal contours of underlying works, but also to yield maps of elemental distribution, thus, suggesting the presence of certain pigments [11][12][13][14][15][16]. The above described techniques are powerful tools, which are rapidly developing and conquering the field of the heritage science.…”