Documentary News Letter (1941)

DOCUMENTARY NEWS LETTER NOVEMBER 1941 we could remove a small section of ceiling to permit using a "Junior" or similar spotlight overhead for really necessary backlighting, everything in the picture was to be lighted from the floor. With deep sets, this necessitated the use of light which would have great penetrating power. This was found in the twin-arc broadsides developed for use in Technicolor. These lamps formed the backbone of our lightmg, supplemented of course with "Juniors," "Seniors," and 170-Amp. arc spots as might be necessary. In passing, it may be mentioned that this technique of using completely ceilinged sets so extensively gave us another advantage: it eliminated that perpetual bane of the cinematographer — microphone shadows! The ceilings were made of muslin, so the sound engineers found no difficulty at all in placing their mikes just above this acoustically porous roof In this position, they were always completely out of camera-range, and as there was no overhead lighting, they couldn't cast any shadows. Yet the ceilings were so low that the mike was almost always in a very favourable position for sound pick-up. I must admit, however, that working this way for eighteen or nineteen weeks tends to spoil one for working under more conventional conditions, where one must always be on the lookout lest the mike or its shadow get into the picture! Optical Problems The next problem was to obtain the definition and depth necessary to Welles' conception of the picture. While the human eye is not literally a universal-focus optical instrument, its depth of field is so great, and its focus-changes so completely automatic that for all practical purposes it is a perfect universal-focus lens. In a motion picture, on the other hand, especially in interior scenes filmed at the large apertures commonly employed, there are inevitable limitations. Even with the 24 mm. lenses used for extreme wide-angle effects, the depth of field — especially at the focal settings most frequently used in studio work (on the average picture, between 8 and 10 feet for the great majority of shots) — is very small. Of course, audiences have become accustomed to seeing things this way on the screen, with a single point of perfect focus, and everything falling off with greater or less rapidity in front of and behind this particular point. But it is a little note of conventionalised artificiality which bespeaks the mechanics and limitations of photography. And we wished to eliminate these suggestions wherever possible. Now it is well known that the use of lenses of short focal length tends in itself to increase the depth of field. So, too, does stopping down the lens. Since the introduction of today's high-speed emulsions, some photographers and some studios make it a practice to take advantage of the film's speed by stopping their lenses down to apertures as low as f : 3.5 or thereabouts when filming interiors. In some instances this is done only occasionally, when for some reason added depth may be desired for a scene or sequence; in others, it is a fixed practice. To solve our problem, we decided to carry this idea a step farther. If using a high-speed film like PIus-X and stopping down to f; 35 gave a desirable increase in definition, wouldn't it — for our purpose, at least — be a still better idea to employ a super-speed emulsion like Super-XX, and to stop down even further. Preliminary experiments proved that it was. However, merely stopping down to the extent which would compensate for the higher sensitivity of Super-XX was still not enough, though we were clearly on the right track. The next step inevitably was to stop down to whatever point might give us the desired depth of field in any given scene, compensating for the decreased exposure-values by increasing the illumination leve'. This, especially on deep, roofed-in sets where no overhead lighting could be used, naturally created another lighting problem. Fortunately, two other factors helped to make this less troublesome than might have been expected. First, we were using, as I have been for some time, lenses treated with the Vard "Opticoat" non-glare coating. In view of the considerable discussion that has arisen since the introduction of these treating methods, I may mention that so far I have found this treatment not only beneficial, but durable. Depending upon the design of the lens to which it is applied, it gives an increase in speed ranging between half a stop and a stop, while at the same time giving a very marked increase in definition, due to the elimination of flare and internal reflections. Secondly, due to the nature of our sets, and the lighting problems incident to our use of ceilinged sets, we were, even before we changed from Plus-X to Super-XX, making considerable use of arc broadsides. In addition to the greater penetrating power of arc light as compared to incandescent, this gave us a further advantage, for the arc is unexcelled in concentrating the greatest illuminating power into a comparatively small unit. The use of these lamps made it possible to use considerably smaller lens apertures than would otherwise have been the case, while still keeping to satisfactorily low illumination-levels, and using surprisingly few lighting units. In many scenes, including even some in the big sets representing Xanadu, "Kane's" exaggeratedly palatial Florida estate, the entire lighting was accomplished using a total of only five or six units, including the arc broads and incandescent spotlights of all sizes. It was therefore possible to work at apertures infinitely smaller than anything that has been used for conventional interior cinematography in many years. While in conventional practice, even with coated lenses, most normal interior scenes are filmed at maximum aperture or close to it — say within the range between f : 2.3 to f : 2.8, with an occasional drop to an aperture of f : 3.5 sufficiently out of the ordinary to cause comment — we photographed nearly all of our interior scenes at apertures not greater than f : 8 — and often smaller. Some scenes were filmed at f: 11, and one even at f: 16! How completely this solved our depth of field problem may easily be imagined. Even the standard 50 mm. and 47 mm. objectives conventionally used have tremendous depth of field when stopped down to such apertures. Wide-angle lenses such as the 35 mm., 28 mm. and 24 mm. objectives, when stopped down to f: 1 1 or f: 16 become to all intents and purposes universalfocus lenses. Depth of Focus Called for But we needed every bit of depth we could possibly obtain. Some of the larger sets extended the full length of two stages at the RKO-Pathe Studio, and necessitated holding an acceptably sharp focus over a depth of nearly 200 feet. In other shots, the composition might include two people talking in the immediate foreground — say two or three feet from the lens — and framing between them equally important action taking place in the background of the set, thirty or forty feet away. Yet both the people in the immediate foreground and the action in the distance had to be kept sharp! In still other shots, Welles' technique of visual simplification might combine what would conventionally be made as two separate shots — a close-up and an insert — in a single, nondollying shot. One such, for instance, was a bighead close-up of a player reading the inscription on a loving-cup. Ordinarily, such a scene would be shown by inter-cutting the close-up of the man reading the inscription with an insert of the inscription itself, thereafter cutting back again to the close-up. As we shot it, the whole thing was compressed into a single composition. The man's head filled one side of the frame ; the loving-cup, the other. In this instance, the head was less than 16 inches from the camera, while the cup was necessarily at arm's length — a distance of several feet. Yet we were able to keep the man's face fully defined, while at the same time the lovingcup was in such sharp focus that the audience was able to read the inscription from it. Also, beyond this foreground were a group of men from 12 to 18 feet focal distance. These men were equally sharp. Setting focus This unorthodox technique, as might be expected, brought with it a completely new set of photographic and lighting problems. Solving them taught us a lot. For example, there is the matter of setting focus on scenes like these, where it is necessary to spread the depth of field over an incredibly great area. Any experienced cinematographer or still photographer will automatically reply, "That's easy— just split your focus between the nearest and farthest points you want to keep in focus!" Yes— — that's the answer — but just where should you focus your lens in order to do this? This is something only practical experience can answer consistently, for while the depth of field of all lenses falls off more sharply in front of the point of focus than behind it, this effect varies not only according to the focal length of ihe lens used, but according to the degree to which it is stopped down and the point upon which it is focused. Gaining this experience