X-radiographyTo investigate the condition of the painted decoration of the chest, x-radiography was used. This imaging technique is valuable in the study of artworks to reveal the state of preservation and build-up of damaged or altered paint layers. It was especially useful in the examination of the chest, which exhibited variable states of preservation, with multiple campaigns of paint apparent on some parts. When exposed to x-rays, pigments containing heavy metals – such as lead or mercury – absorb the radiation more than other pigments and x-ray images show these differences as contrasts of light and dark, revealing earlier paint layers that have been painted over, and changes such as losses of original paint. X-ray images from the front of the chest revealed remnants of early paint layers, similar to traces of paint present on the lid. The detail shows an area where the pigment lead white was employed in the original decoration. Since lead white is a dense and highly x-ray-absorbing pigment, the original paint is visible as light zones in the x-radiograph. The distribution of the earlier paint layers was not evident from visual examination of the surface, since they are broadly obscured by heavy overpaint. These findings were therefore useful in mapping the distribution of the different campaigns of decoration, and indicated which areas should be further explored through analysis of paint samples.
Front of the chest with overlay of x-ray image