Journal of the Society of Motion Picture Engineers (1930-1949)

Reply to the Letter Above The recent letter by Mr. L. Dudley, director of the Laboratory, Odeon Theatre, London, indicates his confusion in reading my paper "Three-Dimensional Motion Picture Applications," published in the June 1951 issue of this Journal. I would therefore like the opportunity to set forth in more detail the explanation of certain phraseology and certain technical aspects with which Mr. Dudley was confused. He points out that "there are three main groups of processes, which might conceivably, but should not be referred to as the "composite or lenticulated system," as I did on page 599 in the Journal. Although he listed the three main groups, he didn't give any indication of how that type of three-dimensional photography could intelligently be referred to. As I see it, each of the groups has one thing in common: namely, that a viewing device on or near the eyes is not needed to vision the three-dimensional results. Each depends on a medium near the picture surface to selectively direct the proper views of the subject to their respective eyes. To produce a stereoscopic vision in the brain, this medium is dependent, in all cases, on one basic fact, that the eyes are displaced. Since the groups, as Mr. Dudley refers to them, are therefore more or less related, there should, in my opinion, be some definite means of referring to them. I could not find anything in the literature which seemed to suitably express this phase of stereoscopy, and as a result chose to refer to the latest refinements of it as the "composite or lenticulated" system. As to the source of the expression "composite," it appears in the reference book Medical Physics, edited by Otto Glasser, Ph.D., Year Book Publishers, Inc., Chicago, 1944-1950, on page 1326 in a treatise on three-dimensional photography. The article under a paragraph heading "Tri vision" reads "Early in 1941, the Winnek Laboratory introduced a new process of composite stereography, now called "Trivision." Composite photography, as defined in Webster's New International Dictionary, means a photograph or portrait made by a combination, or blending of several distinct photographs, either made one over the other, or made on one print from a number of negatives." This, in my opinion, comes very close to describing the condition that exists in the present picture emulsion of the French "Portrait en Relief," the British "Deep Pictures," or the American "Trivision," and other trade processes, all of which stem from the pioneering efforts of H. E. Ives (1902), Lippman (1908) and, of course, Berthier (1896). These refinements of which I speak, consist in segregating and resolving (within limits), by means of a lenticulated surface in front of the emulsion, a continuous changing view, or an infinite number of views of the subject. Thus, when the composite picture is viewed through the same or an identical lenticulated surface, left and right views are selectively projected to their respective eyes. Reasonable freedom of movement of the viewing position either laterally or perpendicularly to the picture is possible, because any two views of the composite, within the angle of coverage of the lenticulation formula employed, will always be a left and right view of the subject, and will be directed to the left and right eyes, respectively. The reason, thus, that I referred to this phase of three-dimensional photography as the "composite" or "lenticulated" system is because, in my opinion, this phraseology most adequately describes this process of three-dimensional photography which in turn has enjoyed limited recent popularity as a result of a more efficient combined use of these two basic features. I chose to use "Focus reaction" rather than "accommodation" in listing my interpretation of the basic factors of depth perception, because it seemed to me that this expression would be more easily understood by the layman, rather than the more technical expression "accommodation," used almost exclusively in ophthalmic practices. Also, I intended to imply that it is not, in my opinion, the difference in the character of the focus of objects which notifies the brain of their relative positions in space, but on the other hand the reaction due to the tensing of the ciliary muscles. In connection with my use of "Stereoscopic vision" as the sixth factor, instead 72