Multi-scale mechanical characterization of the lining canvas of The Night Watch by Rembrandt

This contribution presents a multi-scale experimental analysis of the mechanical properties of the lining canvas of <i>The Night Watch</i> (1642), a large-format canvas painting by Rembrandt van Rijn. The original canvas has deteriorated significantly, leaving the lining canvas as the primary load-bearing component. Mechanical properties, including Young's modulus, tensile strength, and strain at fracture, are evaluated at three hierarchical levels (fibre, thread, canvas) using advanced in-situ tensile testing combined with optical profilometry, optical microscopy, and Digital Image Correlation. The study distinguishes between the <i>composite</i> properties of the lining canvas, reflecting the combined behaviour of fibres, wax resin, and voids, and the <i>intrinsic</i> properties, representing the fibre material alone. Scaling laws are established to relate stiffness and tensile strength to the characteristic material length scale, enabling predictions of canvas-scale behaviour from non-invasive fibre-level analyses. These findings may inform future conservation strategies for the canvas of <i>The Night Watch</i> and other paintings.