chalk-rich sketch
The whitish, blotchy appearance of the dog (fig. 1) has puzzled researchers from the Operation Night Watch team from the start of the project. It turns out to be related to a light-coloured painted sketch that Rembrandt used to set up the initial composition of The Night Watch. The sketch paint is rich in chalk. The new imaging techniques were able to visualize this chalk-rich sketch in many areas of the painting (fig. 2).
a new discovery
The use of such a sketch layer is a new discovery and has not found before in Rembrandt’s paintings. In combination with the brown colour of the quartz ground (that functions as a midtone), and the use of fluent black sketch lines, it seems a very efficient method to initially define the composition and introduce volumes.
spontaneous working method
This practice is consistent with Rembrandt’s seemingly spontaneous working method of developing the composition directly on the painting. The same applies to the dog, which in particular is very efficiently painted. His outlines and volume were initially defined with the light chalk-rich sketch layer and subsequently only covered by thin paint layers, leaving large areas of the brown ground and probably also parts of the light sketch deliberately exposed as part of the modelling (Fig. 3).
abrasion caused by past treatments
The light chalk-rich sketch is now partly visible because of abrasion caused by past treatments, resulting in disfiguring whitish areas (Fig. 4). We also assume that due to degradation, the light sketch looks even lighter today than it was intended by Rembrandt. The now exposed light-coloured sketch causes a disturbing tonal imbalance because these outlines now appear much lighter than the yellowish highlights Rembrandt added in a final painting stage.
