1. A method of combining two or more separate images into an optical composite, which method comprises projecting onto a screen that contains transparent or translucent semiconductor material, with ultraviolet light whose photon energy exceeds the band-gap energy of the semiconductor material, a silhouette of each of the foreground images to be inserted into a background image; projecting onto the said screen from the front each of the appropriate foreground images such that each image appears on the screen congruent with its ultraviolet silhouette; projecting onto the screen from the rear the appropriate background image; and photographing the result from the front of the screen.