American Cinematographer - December 1960 - 28

Cinematography
For
Television Films
Lack of important component in average
home TV receiver dictates certain lighting
and photographic requirements for best
reception of television films.
By

IN TELEVISION film photography, the ratio of key to fill light should
not exceed 2y2-to-l, and the maximum brightness ratio of scene
elements should range between 20-to-l and 30-to-1.

THE FOLLOWING article is reprinted from the new
American Cinematographer Manual, and typifies the many
technical articles helpful to cinematographers which appear
throughout this latest publication of the American Society
of Cinematographers. (Descriptive illustrations have been
added here to clarify technical points.) The author,
Edward P. Ancona, Jr., was formerly staff engineer for
the Motion Picture Research Council's Television Film
Engineering Department.-EDITOR.

characteristically are viewed with some room lights on. The resulting
ambient light falling on the receiver screen tends to
degrade and wash out the image shadows. Also, if
the receiver brightness control is improperly ad¬
justed, a further degradation of the shadow scale
will take place. The combination of these effects
requires that the television film photographer avoid
scenes or effects which rely upon accurate or subtle
rendition of shadow detail.
Another factor, even more serious in its effect
upon the correct rendition of grey scale values on
the home receiver, involves a portion of the receiver
circuit known as the "d.c. restorer." The function
of the d.c. restorer might be described as that of
an automatic brightness control which maintains a
constant effective brightness setting on the picture

'T'ELEVISION RECEIVERS

734

EDWARD

P.

ANCONA,

JR.

tube as the scenes vary in average brightness. In a
receiver with a d.c. restorer, scenes will be correctly
represented regardless of their average brightness;
for instance, a dark, low key shot will be repro¬
duced as a dark low key scene, and a fade-out will
make the picture tube black. Likewise, a high-key
shot, such as an actor against the sky, will be repro¬
duced as a bright scene, and the middle tones, such
as the actor's face, will be correctly rendered. In a
receiver without a d.c. restorer, however, the dark
low key scene will be reproduced as a washed out
grey scene, and the fade-out will appear as a fade
to a medium grey. The high-key shot, in the receiver
without a d.c. restorer, will be reproduced with in¬
sufficient brightness, and the middle tones, such as
the actor's face, will be reproduced too dark. The
receiver without d.c. restoration will correctly repro¬
duce scenes of average content, but high-key ("cow¬
boy against the sky") and low-key ("day for night"
or large areas of black) scenes will not reproduce
correctly.
This behavior of the receiver without d.c. restor¬
ation is similar to the failure of a reflected light
exposure meter to indicate correct exposure on some
scenes. This type of meter will give the correct ex¬
posure for "average" scenes but will give erroneous
readings for scenes with large dark or light areas.
An incident light meter, of course, would give the
correct exposure in any case, since its readings are a
function only of the intensity of light falling on the
scene.
To achieve the most effective reproduction on
receivers without d.c. restoration, the cinematogra¬
pher should therefore attempt to balance lighting
AMERICAN CINEMATOGRAPHER
American Cinematographer - December 1960

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