A television system combines signals representing a picture derived from a foreground scene moving in front of a backing, with a background scene. An input processing circuit mixes a color from the background scene, preferably different from the backing color, with certain colors in the composite foreground and backing picture. A first combiner responsive to the picture and background scene representing signals determines picture zones where false colors are created at transition points between the foreground scene and the backing. At transitions, e.g. a transparent object, between the foreground and background scenes in the resultant picture transmitted by the system, the colors are modified progressively such that a viewer no longer sees the edges or the reflections due to the backing, but rather a slight blur blending perfectly with the background and foreground scene colors.