a color temperature of 5600 degrees kelvin. Television cameras can be adjusted
to operate under either of these color temperatures but not both at the same
time.
Therefore, when using lighting instruments outdoors to supplement
available sunlight, the color temperature of the available light and the
lighting instruments used to supplement that light must be matched. Since we
can't change the color temperature of the sun, we must match the color
temperature of the lighting instruments to the sun.
a. The easiest method of changing a lighting instrument's color
temperature is by attaching a dichroic daylight filter to the front of the
lighting instrument.
A daylight dichroic filter will change the color
temperature of the illumination emitted by the lighting instrument to 5600
degrees kelvin, matching the color temperature of outdoor illumination. A blue
gel can be used as a substitute for a dichroic daylight filter, but care must
be taken to ensure that the gel does not change the illumination beyond 5600K.
Otherwise, the scene will take on a bluish tint.
b. When shooting indoors, matching color temperatures of different light
sources can be even more difficult than when shooting outdoors. Some interiors
are illuminated by the daylight that comes through large windows, others with
fluorescent lighting, and still others use desk and floor lamps to augment the
daylight that is coming through windows. The major problem here is not so much
how to supply additional light but how to match the various color temperatures.
2. The most difficult problem is having to shoot your subject with a large
window in the background.
Often a general wants to make his or her brief
statement from behind a desk, and the desk may be located in front of a large
viewing window. There are two lighting problems in this situation. First of
all, there is a problem identical to that of a person in front of a bright
background. If you set the iris according to the background brightness, the
general in front tends to turn into a silhouette. If you adjust the iris to
the general, the background is overexposed. Secondly, the color of the light
coming through the window does not match the illumination used to light the
room.
If you adjust the camera to the daylight color temperature, the
illumination will appear bluish. Let us take a look at some possible solutions
to these problems.
a. The best method of controlling both of these problems is to draw the
curtains or blinds and light the set using portable lighting instruments.
Unfortunately, not all office windows have curtains or blinds.
Another easy
method of controlling these problems is to "shoot" your subject using only
closeups, thus eliminating most of the background. The "closeup only" method
is not always practical either.
For instance, some people just do not look
good when shown close up.
b. If you must shoot the scene with the window in the background, it is
possible to cover the windows with large plastic neutral density and color
correction filter sheets. Neutral density (ND) filters act like sun glasses,
reducing the intensity of the light without changing color temperature. Color
correction filters, on the other hand, change the color temperature of the
light. A combination neutral density and color correction filter sheet can be
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