This paper presents a new design, calibration procedures, and an optimized capturing strategy, of a 3D imaging system for capturing very large paintings. It describes relevant design requirements and constraints, various (improved) calibration steps, and additional capturing automation, aimed at optimally and efficiently capturing the characteristic topographical features, such as impasto and craquelure, of (17th century, Dutch) paintings. The 3D imaging system was used to capture Rembrandt van Rijn's 'The Night Watch' (1642), a painting with a surface area of more than 17m2. We highlight some preliminary result of this scanning campaign and possible applications such as painting documentation, condition analysis, and visualization.