LINE DESCRIBING A CONE is what I term a solid light film. It deals with the projected light beam itself, rather than treating the light beam as a mere carrier of coded information, which is decoded when it strikes the flat surface (the screen). It is projected in the normal way, on a 16mm film projector. Though inevitably there will be a wall that limits the length of the beam, a screen is not necessary. The viewer watches the film, by standing with his, or her, back towards what would normally be the screen, and looking along the beam towards the projector itself. The film begins as a coherent line of light, like a laser beam, and develops through the 30 minute duration, into a complete, hollow cone of light. Line Describing a Cone deals with one of the irreducible, necessary conditions of film: projected light. It deals with this phenomenon directly, independent of any other consideration. It is the first film to exist solely in real, three-dimensional, space.