
Late paintings of Rembrandt van Rijn (1606-1669) are among the most admired works of the Dutch seventeenth century. Saul and David, in the collection of the Royal Picture Gallery Mauritshuis (The Hague, Netherlands), depicts the Old Testament narrative in which the king, consumed by jealousy, listens to David playing the harp moments before hurling his spear at the young musician. This work offers intriguing problems for both art historians and conservation scientists, in part because stylistic differences in paint handling have led to disagreement on the attribution of Rembrandt’s authorship. The objective of our research was to determine whether the observed stylistic differences could be correlated with material differences.

Stylistic differences are most pronounced in orange-red areas of the painting. For example, the highlights of David’s left, orange-red sleeve in front of the harp, which convincingly convey the tucked pattern of fabric, contrast with the loose, slashing orange-red brushstrokes that lack three-dimensionality, applied along the edge of Saul’s cloak with a wide brush. Such differences in paint handling have been associated with two paintings stages by scholars since the late 1960s.
The areas of the painting having pronounced stylistic differences were investigated with two macroscopic chemical imaging methods, x-ray fluorescence (XRF) and reflectance imaging spectroscopies.
The areas of the painting having pronounced stylistic differences were investigated with two macroscopic chemical imaging methods, x-ray fluorescence (XRF) and reflectance imaging spectroscopies. The pigments used were identified and their spatial distribution was mapped. The mapping results from reflectance imaging spectroscopy (RIS) show that the passages rendered in more detail and associated stylistically with the first painting stage, such as the orange-red color of David’s garment, were painted with predominately red ochre (an iron oxide) and vermilion (mercury sulfide). This mixture is represented by the red color in the RIS map. The elements iron (Fe) and mercury (Hg) were both detected with XRF imaging spectroscopy.

The regions of loose, bold brushwork, such as the orange-red slashing strokes in the interior of Saul’s cloak, associated with the second painting stage, were painted with predominately red ochre without vermilion (green color in RIS map).
The regions of loose, bold brushwork, such as the orange-red slashing strokes in the interior of Saul’s cloak, associated with the second painting stage, were painted with predominately red ochre without vermilion (green color in RIS map). Iron, but no mercury, was detected with XRF imaging spectroscopy. Interestingly, material analysis of the awkward, curved highlights added to David’s right sleeve behind the harp, associated stylistically with the second painting stage, also shows they predominately consist of red iron ochre, but do not contain Hg or vermilion.

The paint used in stage one consists of a mixture of red iron ochre and vermilion, whereas the paint in stage two consisted of predominately red iron ochre without vermilion.
The macroscale imaging results were confirmed and extended with light microscopy and scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) of cross-sections taken from regions of stylistic differences associated with the two painting stages, including one sample each from the right and left sleeve of David, and one from the interior of Saul’s cloak. Specifically, the paint used in stage one consists of a mixture of red iron ochre and vermilion, whereas the paint in stage two consisted of predominately red iron ochre without vermilion. SEM-EDX also identified a trace component, barium sulfate, associated with the red ochre of the second stage revisions. Combining mapping information from two spectroscopic imaging methods with localized information from microscopic samples has clearly shown that the stylistic differences observed in the paint handling are affiliated with differences in the chemical composition of the paints.