Rembrandt’s The Night Watch (1642) has been wax-resin lined, which involved attaching a new canvas to its reverse using a beeswax-resin mixture to achieve structural stabilisation and shielding against environmental humidity. We investigated the effect of wax-resin lining on water transport in The Night Watch using a one-dimensional, multi-layered water transport model based on ideal diffusion. Model input parameters were estimated using dynamic vapour sorption experiments. The paint layer response in the environmental conditions of the BIZOT Green Protocol was evaluated. During the fastest allowed RH fluctuation in BIZOT, water concentration in the paint layer of wax-resin lined paintings only reached 30% of the maximum concentration at static RH conditions (60% RH). Furthermore, we show that the water sorption capacity of the wax-resin adhesive of The Night Watch increased after ca. 50 years of natural ageing. Modelling results indicated that the effect of this increase on the overall response is minor.
In 1990, Rembrandt's The Night Watch was attacked with concentrated sulphuric acid. This study reassesses the affected area and aims to identify and characterise any secondary degradation products, as well as any challenges for the conservation treatment. A comprehensive analytical approach, using macroscopic X-ray fluorescence (MA-XRF), macroscopic X-ray powder diffraction (MA-XRPD), optical coherence tomography (OCT), and light microscopy, scanning electron microscopy combined with energy-dispersive X-ray (SEM-EDX) analysis, micro attenuated total reflectance Fourier transform infrared (& micro;-ATR-FTIR) spectroscopy and synchrotron radiation micro X-ray powder diffraction (SR-& micro;-XRPD) of three paint cross-sections, permitted the confirmation of anglesite (PbSO4) and extensive lead soap formation in the affected areas. Additionally, mock-ups were prepared and analysed to reconstruct the entire sequence of events of the acid attack. Current estimations predict that some of the damage to the paint layers will become discernible after varnish removal and that local consolidation of the fragile surface might be required.
In 1990, Rembrandt’s The Night Watch was attacked with concentrated sulphuric acid. This study reassesses the affected area and aims to identify and characterise any secondary degradation products, as well as any challenges for the conservation treatment. A comprehensive analytical approach, using macroscopic X-ray fluorescence (MA-XRF), macroscopic X-ray powder diffraction (MA-XRPD), optical coherence tomography (OCT), and light microscopy, scanning electron microscopy combined with energy-dispersive X-ray (SEM-EDX) analysis, micro attenuated total reflectance Fourier transform infrared (µ-ATR-FTIR) spectroscopy and synchrotron radiation micro X-ray powder diffraction (SR-µ-XRPD) of three paint cross-sections, permitted the confirmation of anglesite (PbSO4) and extensive lead soap formation in the affected areas. Additionally, mock-ups were prepared and analysed to reconstruct the entire sequence of events of the acid attack. Current estimations predict that some of the damage to the paint layers will become discernible after varnish removal and that local consolidation of the fragile surface might be required.
Abstract Smalt is one of the main blue pigments in Rembrandt van Rijn’s The Night Watch (1642). Smalt is a cobalt-containing potash glass, ground to a powder to be used as an artists’ pigment. In this study, three smalt-containing paint samples from this painting were studied using synchrotron radiation-based micro-X-ray fluorescence (SR-μ-XRF) tomography. To study the original intentions of the artist, the degradation phenomena taking place in the paint and the best preservation methods for the painting, a fuller understanding of the smalt-containing paint mixtures is desired. The smalt particles in Rembrandt’s paints show a wide variety in size and elemental composition. Elements related to smalt are, e.g., cobalt, potassium, arsenic, bismuth, nickel, and iron. The heterogeneity is very high among the particles within one paint sample. Different clusters of particles can be established based on the intensity of bismuth. This variety could be caused by heterogeneity in the cobalt ore, the glass-making process, the use of multiple types of smalt or it might be the result of in-situ degradation. Next to the smalt, the volume percentages taken up by other components of the paint are semi quantitively estimated based on elemental information. This information can be used in follow-up studies to improve the accuracy of models and the representativeness of reconstructed paint mockup samples. SR-μ-XRF tomography proves to be a valuable tool for the identification and quantification of complex heterogenous smalt paints.
