Motion Picture Herald (Jul-Aug 1936)

Maintain your projection equipment religiously ; you'll reap reivards in the world. — F. H. R. F. H. RICHARDSON'S COMMENT AND ANSWERS TO INQUIRIES ANSWERING INQUIRIES CONCERNING TELEVISION JOHN L. SIMMONS of Jacksonville, Fla., has written me as follows : "I note your expressed disbelief that television will be unable to serve motion picture theatres unless or until radical changes have been made in some parts of its structure. Will you be good enough to tell us exactly upon what you base that opinion ? "Thus far everything written concerning television has been couched in such highly technical terms and so cluttered up with X, Y and Z formulas, cube roots and symbols that have no meaning to any but trained engineers, that to me, and I think the average man, they mean just exactly nothing at all. Would it be possible, Mr. Richardson, for you to reduce all this scientific flub-dub to simple language that can be understood by average humans — myself for example?" What is asked for here is really out of my line. I could write but very little, all by myself, that would not cause the television experts to elevate their honorable noses at more or less sharp angles. Moreover, matters like television are not easily "explained clearly" entirely in lay terms. However, with the help of some persons more familiar than I with the mysteries of television, I will attempt to give Mr. Simmons and others who have made similar inquiry from time to time, some idea of "what it is all about." First of all, did you ever separate an ordinary photograph into tiny squares, each, say, one sixty-fourth of an inch on each side, and then, by photography, enlarge each piece and reassemble them, each in its proper place upon a canvas screen, you would have an enlarged picture exactly the same as the one you cut to pieces. That is about what television does so far as the picture itself is concerned. A beam of light "picks up" minute successive "spots" in the subject of the television broadcast, each section of the light beam acquiring an intensity in accordance with the tone (light) characteristic of the subject. Exactly as in sound reproduction, this beam of light, its brilliancy constantly varying in accordance with the successive spots picked up (or that it has passed through, if that makes it plainer) as it moves in a straight line across the picture, is transformed into electric current, the strength of which varies as the brightness of the beam varies. This enormously weak current then is stepped up to a very high level, if it is to be transported through the air, or to a moderate level if it is to travel by wire. At the receiving end (this might be a theatre) it will be picked up just as is the radio impulse, retransformed into a beam of light, and by a suitable optical system, projected on a screen in magnified form. And now comes the next big item — so big that it is almost beyond belief to the uninitiated. Upon the screen only just one of those "spots" picked up can appear at one time, the remainder of the screen being blank. How then does the whole picture appear? It appears because the eye has persistence of vision which causes it to retain, for a small fraction of a second, images impressed upon it. These "spots" are projected to the screen continuously. Persistence of vision lasts a sufficient time to enable the retention of all the spots in each picture until the whole picture is complete and the next one is under way. Let us now examine a few of the various items of operation involved. Disregarding details, of which there are plenty and to spare, and without an intent to describe actualities of practice except in a general way, let us assume we are to broadcast a motion picture positive print, with a beam of light focused thereon of such tiny Other Articles In addition to the material on this page, Mr. Richardson's columns of this issue also contain: Why Screen Illumination Fades Page 28 Another Old Timer Passes Page 30 Suitability of Mazda Light Page 30 Making Data Available Page 30 Monopland and Biplane Lamps Page 31 Prefers Mazda Lamps Page 32 Determining Screen Needed Page 33 One-Man Rooms Make Jobs Scarce Page 33 Vacuum-Clean Lamphouses Page 34 Projection in Sing Sing Page 34 Remarkable Sound Quality Page 36 New Suprex Arc Lamp Page 36 Way of Light Refraction Page 36 Projection Room Photos Page 36 diameter at the point of contact that 343 of its diameters will just equal the width of the picture in the direction it is to be "scanned." Let us assume this spot to be focused upon the upper left hand corner, and that it moves in a straight line across the frame (picture) to the right and that upon reaching the completion of its travel it drops down (the movement may be either horizontal or vertical) a distance exactly equal to its own diameter, flashed across the picture again, and continues that operation until the entire picture has been covered, or "scanned." In this operation for the sake of clarity we will regard each diameter of the beam, as it moves across the picture, as a separate "spot," so that it is no large jump to imagine each separate spot in the photograph as being picked up separately, even though the picking up be rapid and continuous. We also may see that the length of the light beam representing each "spot" will be of brightness in accordance with its photographic density. In ordinary motion picture projection, the beam of light that has passed through the film, carries the photographic shading of the whole picture within it, while the picture is over the aperture, but (try to comprehend this clearly) in the case of television the variations in photographic density are carried in the length of the beam itself, since various sections of its length have passed through various sections or "spots" of the picture area. In other words, were we able to view the entire length of the light beam, its brightness at various sections being visible, we would discover that in its length it carried the entire photographic shadings of the picture it had scanned. True the movement of the beam is extremely rapid, as well as continuous, nevertheless in effect it has rested upon every point or "spot" in the entire picture for an infinitesimal fraction of a second. Hence we may say that every spot has been viewed (scanned) separately. And right here I feel competent to explain the basis of the opinion cited by Friend Simmons. We have seen that only July 25, 1936 27