The improper illumination of cultural heritage buildings and monuments can be a source of enormous light pollution, which can have a major impact on the overall environment of the illuminated area. Such lighting can be the result of carelessness or a poorly designed lighting system. This paper presents one of the methodologies that can significantly reduce light pollution, especially spilt light out of building façades. The methodology is based on using luminaires with specially made shutters and an appropriate silhouette of the object. The shutters are designed with the help of photos of the object and the location’s sizes measured. The methodology was tested during the renovation of the lighting systems of different churches in Slovenia and is described using the example of the Church of St. Thomas near Ptuj, Slovenia (N46°28.9554′, E16°0.7416′). The results show that the methodology is effective and can significantly reduce light pollution that occurs when such buildings are incorrectly lit.

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