In regard to lighting, cross-fading refers to the transition from one light scene to another. The cross-fading time is the period required for the scene change. It varies between instant change and a transition of several hours. High-contrast scenes with a short cross-fading time generate considerable attention. Subtle transitions with lengthy cross-fading times, on the other hand, are hardly noticeable. The scene change can be initiated by the user, a sensor, or a timer.