Talking pictures : how they are made, how to appreciate them (c. 1937)

The Road Ahead covers a commercial method by which pictures with length, breadth, and thickness can be seen practically with the unaided eye. Experimental demonstrations of this kind have been made before small groups, but as yet are not practical for large theatres. We know that in stereoscopic photography light is admitted to the camera through two lenses set apart at the distance between the average person's eyes. One of the images is dyed an orange, the other a blue-green. They are printed together on a single film, but the two images slightly overlap each other, a condition that results from the distance between the two lenses. With this method it is physically impossible to watch a projection with the naked eye. The flicker is abnormal and the two images superimposed produce an almost hopeless blur. The unaided eyes cannot stand the strain caused by this flicker for more than a few minutes. Put before your eyes, however, a pair of spectacles with one orange lens and one blue-green lens and magically the blur disappears, and on comes the third dimension thickness. Each eye now sees the image it would have seen had it been in the place of the corresponding lenses of the camera. The scientific "why" of this is too complicated to be discussed here. But enough has been told, it is believed, to interest those alive to the possibilities of a future all-third-dimension cinema in reading the extensive literature which exists on third dimension photography. Long before the time of Edison, stereoscopic photography was the hobby of thousands of inventors, and the great problems introduced by a moving picture have only stimulated more intensive research. [287]