Abstract: Apparatus and methods are described whereby a projected television image is divided into two horizontally displaced images, and an observer wears glasses to synthesize three-dimensionality from the 2-D image. Switching means are provided so that the components associated with creating the 3-D effect may be made operative or inoperative, either mechanically or electrically. One or more wedge prisms or holographic optical elements are mounted on a frame along with polarizing filters, and a lever is used to transfer these elements into and out of the beam of a projected television image. Alternatively, an electrically or acoustically activated spatial light modulator and liquid-crystal polarizers may be left in the path of the projected beam and made operative and inoperative by way of electrical signals. The invention may be used with both single-source and multi-source projected images, and may be used in conjunction with both frontal and rear projection.