Today, Light Art is an independent art genre alongside painting, sculpture or photography, which can be found in the superordinate categories of sculpture and installation. Contemporary light artists work primarily with artificial light as a light source. One can only speak of light art if the use of light sources serves aesthetic purposes. As a rule, this does not apply to installations whose purpose is merely to make objects visible in the dark by means of illumination, or which have a profane sign character (such as the coloured lights in traffic lights), or to commercial illuminated advertising that does not go beyond the scope of conventional design. Most works of light art require the virtual absence of natural (day) light and of competing artificial light sources in order to unfold their full effectiveness.