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

Stijn Legrand,Matthias Alfeld,Geert Van Der Snickt,Koen Janssens,Wout De Nolf,Frederik Vanmeert,Joris Dik

doi:10.1186/2050-7445-2-13

Abstract

AbstractThe 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.

Highlights

Historical paintings are considered to be among the most precious cultural heritage artefacts and have been the subject of intensive studies for decades
This review focusses on the examination of easel paintings, i.e., painted renditions realized on a moveable substrate
infrared reflectography (IRR) has become a routine form of analysis in many painting collections, almost exclusively for the study of carbon-based underdrawings in paintings from the 16th century and earlier

Summary

Introduction

Historical paintings are considered to be among the most precious cultural heritage artefacts and have been the subject of intensive studies for decades. In a number of cases where the results of MA-XRF do not significantly differ from those obtained by XRR, for example in the case where very thick overpainted layers of lead white are present, this system has allowed to obtain contrast-rich imaging information This complementarity was recently underscored during the examination of a painting by R. It is built up of a number of strongly contrasting coloured areas and has a fairly simple stratigraphy, in most cases consisting of only one paint layer applied on a calcite ground. The technique is valuable for the study of near-surface features, notably translucent layers such as glazes and varnish [51]

Conclusions

33. Van Asperen de Boer J

45. Legrand S