Comparison of x-ray absorption and emission techniques for the investigation of paintings

Transmission radiography is an excellent and easy to use method to visualize the internal structure and spatial distribution of heavy Z pigments in the paint layer of 15th to 17th-century panel paintings. It is used to examine the creation process of the artist (e.g. changes in composition, underlying paintings, etc.), to identify older restorations and to solve authentication problems. However, some historical paintings have white lead-based preparatory layers. As a result, the pictorial layer can hardly be visualized in the radiographic images. This problem becomes even more important for 19th and 20th-century paintings due to the introduction of low-Z white pigments. In this investigation, we explored the possibilities of 4 less common radiographic techniques in order to circumvent the mentioned problems. For this, we applied the techniques on 4 panel paintings with an identical figurative composition made by the artist Peter Eyskens.