Charcoal drawing of the Night Watch in Caves Zonnenberg

Between September 2018 and June 2019, a restoration was carried out on a black-and-white marl copy of Rembrandt van Rijn's The Night Watch, located in the Zonneberg Caves in Maastricht. This copy, created by Jules Sondeijker (1865-1950) between 1902 and 1904, exhibited significant damage, including scratches in the soft marl, which necessitated urgent restoration.

Damages and vandalism

The Night Watch imitation suffered significant damage due to individuals carving scratches, names, and dates (e.g., '89 or ROLO) into it with sharp objects. Since the cave system was closed to visitors in 1990, such vandalism ceased. The most severe damage occurred in the lower part of the painting, where frequent contact with the unbound black pigments had partially erased the shapes. Higher up, several carved names were found in an otherwise intact area. Additionally, during the restoration, splinters of glass were discovered in two places, indicating that bottles of beer had been forcefully smashed against the painting in the past.

The restoration

The restoration of the black-and-white copy of The Night Watch in the Zonneberg Caves in Maastricht was conducted under challenging conditions, including high humidity, low temperatures, and the remote location. The team of conservators, consisting of at least two individuals, worked within these constraints to address various issues, including filling scratches, retouching, reconstructing missing parts, and removing residual alkyd paint.

To repair scratches, mortar in a color matching the marl was applied. Different black pigments were used for retouching based on the tonality and depth of the original black. Fine brushes were employed to replicate the blended character of the paint, while larger missing areas were filled in with pastel chalk. White sections were retouched with whitewash due to its favorable aging properties and texture.

Restoration of the upper half of the painting was performed from scaffolding, focusing primarily on treating scratches. The lower part and certain figures required more extensive reconstruction, guided by old photographs and detailed images of the original The Night Watch. Missing sections were tentatively reconstructed using pastel chalk and black pigments, allowing for the restoration of intricate details, including the faces of Willem van Ruytenburgh and his companion Frans Banning Cocq.

Natuurmonumenten, as manager of the Zonneberg Caves, initiated the restoration in cooperation with Maastricht Underground and Stichting Recreatief Berglopen. Financial support for the project was obtained from the Elisabeth Strouven Fund and DSM.