Night illuminations of historical architectural objects have been discussed. In order to simulate light effects on the existing object of the Royal Palace in Łobzów, renderings with a defined illumination were made. The author proves that illumination is not only a matter of engineering, but also an art. The possibility to influence the reception of architecture through illumination and the possibilities to simulate illuminations using computer software are investigated. It tries to answer the question whether the method of work, which requires utilization of precise data, deprives the designer of artistry.