Movie Makers (Jan-Dec 1951)

359 Photographs by Leo J. HefTernan, FACL FIG. 4: Scenes of less than full brightness range, such as this 1:6, may FIG. 5: Lighting contrast range is important factor in subject be exposed selectively in 1:16 sensitivity range of color film. contrast. Here reflector lightens shadow side of subject. even 40. Something, obviously, has got to suffer exposure-wise. The solution here was to determine correct exposure for the most important element of the scene — which, when in doubt, should be the flesh tones of the subjects. By exposing for them the white boat has been washed out. But if we had exposed for the boat, both the flesh tones and the large surrounding dark area would have suffered. Fig. 3 provides another example, and another solution. Here again subject brightness range is well over 1:30, but the moving, dramatic action both justifies the scene and distracts from its extremes of contrast. The exposure for such a scene would be fitted into the film sensitivity range so as to preserve sparkle in the highlights while the shadows are left to take care of themselves. EXPOSURE FOR LESSER RANGE And now we come to that 6 inch ruler mentioned in our opening paragraph, the one which can be fitted successfully in varying positions along the 16 inch rule. The smaller ruler may be visualized as representing a scene in which subject brightness range is within narrower limits of contrast than the 1:16 ratio of an average scene. Fig. 4, showing the light-clad bather surrounded by lighttoned water, is such a scene. In it the subject brightness range is likely to be no greater than 1 :6. When the brightness range of a scene is less than the complete 1:16 sensitivity range of the film, several facts become interestingly apparent. First, the sensitivity range of the film now provides some latitude for error in the selection of an ideal exposure. While an ideal exposure is still the most desirable, an error of as much as 1% stops might still be absorbed satisfactorily by the film. Second, and perhaps more important, is the fact that a scene of narrow contrast range (such as our 1:6 view) permits the cameraman a conscious control of the tonal values of his image. If, with such a scene, he wishes the overall effect to be bright and gay, he will purposely overexpose somewhat. This will render the light elements of the scene in extremely high key, at the same time that it opens up the dark or shadowed elements of the picture. Contrariwise, if an ominous, stormy effect is the one desired, some underexposure will deepen the shadows and tone down the highlights. PLACING THE PICTURE RULE Here the 16 unit rule shown in the diagram represents the total range of film sensitivity, with its lower half standing for the wider apertures of more exposure, its upper half the smaller apertures of less exposure. Superimposed on this background is a 6 unit rule, representing a scene of 1 :6 brightness range, in three different relationships to the film's sensitivity. It will be seen first that rule A-A' is positioned centrally along the 1:16 sensitivity range, thus creating for the scene an exactly average exposure. For high-key results, however, the 1 :6 scene might be exposed at the B-B' position on the sensitivity range, thus lightening its values and lessening its contrast. Or for a low-key effect the cameraman might choose the C-C relation to the film's sensitivity. Thus, by a conscious control, three quite different — but all usable — exposures are created. LIGHTING AFFECTS CONTRAST An always important factor in subject contrast range is lighting contrast range. In every scene outdoors, and in most scenes indoors, the light illuminating a scene will come from one main source which casts shadows. These shadows are brightened somewhat by fill light, meaning that the supplementary light fills in the shadows. Outdoors, light from the sky will supplement sunlight, thus supporting the shadow side [Continued on page 377] 0 1 2 3 4 ; 6 7 8 9 10 1 1 12 12. 1 14 15 16 A A' <C ' !B 1 | Q'l 1 SENSITIVITY RANGE of color film is represented above by the 1:16 ruler in the background. Positioned on it for selective exposures of a 1:6 brightness-range scene are the rules A-A' for normal exposure, B-B' for high-key exposure and C-C for low-key exposure.