10 most important things to know about lights

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THE 10 MOST IMPORTANT THINGS TO KNOW ABOUT LIGHTS
1. The light you attach to your camera is usually unflattering. The
camera light is great for getting an image where you were unable to
get one otherwise, but it casts unflattering shadows on your talent.
But if you must . . .
Because modern cameras are fairly sensitive, it is possible to
attach a 25 watt light to the camera to illuminate a narrator or
newscaster. This small amount of light does not drain the batteries
very fast, yet provides a little extra punch even in the daytime if
the talent is standing near the camera (and thus near the light). One
way to ameliorate the "mug shot" shadow look is to place your camera
light on an offset arm; now the light hits the talent from slightly to
the side.
2. The best lighting is "3-point lighting". Hit the talent with a
key light from above and to one side. This provides most of the
illumination and creates most of the shadows. From above on the
opposite side, hit the talent with a soft, diffused light. This fill
light fills in the shadows, taking away their harshness. From above
and behind the talent, use a back light to create a rim around the
hair and shoulders, making the talent look three dimensional on the
two dimensional TV screen. Whenever possible, add a fourth point to
your lighting system, the set light that determines the brightness of
the background behind your talent.
3. Pay attention to color temperature. Fluorescent lights are sort
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of greenish. Common incandescent lighting is reddish (about 2000
degrees K color temperature). Quartz halogen TV lights are also
reddish (3200 degrees K). Outdoor light is usually bluish, (about
5400 degrees K) except during sunrise and sunset. People's skin looks
strange when illuminated by more than one type of light. The bluish
light from a window could make one side of the talent's face look
pallid and ghost-like, while indoor lighting may make the other side
of the face look red and sunburned. To balance your colors, try to
use only one type of light in the scene. If shooting outdoors or next
to a window, and you wish to "fill" the dark side of an image with
incandescent light, place a 1/4 or 1/2 blue color correction gel over
the light to reduce its redness. Thus bluish light will be coming
from both sides and you can color balance your camera to make the
flesh tones look correct everywhere.
Handling the above situation a different way, you could place a
large, slightly amber 85B gel or 1/4 CTO gel over the window to "warm
up" the blue light coming in. Thus you have reddish light from the
window and reddish light from the interior incandescent lamps
illuminating your talent.
Placing a blue gel over a standard tungsten studio lamp reduces
its brightness significantly. The perfect solution would be to use
studio lights that were bluish and matched the outdoor color
temperatures. These are called HMI lights (5600 degrees K). Because
none of the light is wasted by filters, HMI lights are twice as
efficient as quartz. They are perfect for filling in shadows in
outdoor scenes.
In offices where fluorescent lights provide most of the
illumination, one could gel the tungsten lights as before, again
wasting a lot of electricity. Or you could gel the fluorescents to
match the tungstens. The most efficient solution is to employ more
fluorescent lights, such as the Lowel Light-Array, or one of the
Videssence, or Mole-Richardson models. These are banks of
fluorescent tubes that can be adjusted in brightness and used to
complement the existing office lighting (which because it comes from
above never looks that terrific by itself). It is also possible to
change the tubes in fluorescent lighting so that the colors can be
made warmer or at least be made to match the colors in other lights.
You might try Softtube 3200 degree K tubes to match studio quartz
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lights. Two additional benefits of fluorescent lights: they consume
less than half the power (per amount of useful light) of their
tungsten counterparts, and consequently require less noisy and
expensive air conditioning.
4. Always carry extra light bulbs. There is no excuse for going home
because the light bulb burned out and you didn't have an extra.
5. When replacing tungsten halogen (quartz) studio lights, be sure
to:
a. Wait for the bulb to cool off so you don't fricassee your fingers.
b. Handle the new bulb within its plastic wrapper so that you don't
get finger oils on the glass. The oils will destroy the glass when
the bulb heats up.
6. Never reposition a tungsten halogen light while it's still lit.
The white hot filament is very delicate and may break if you bump the
lamp. Switch the lamp off, wait one second, and then move it.
7. Don't overload power circuits. Electrical outlets for homes are
generally equipped for 15 to 20 amps per circuit (and that circuit may
be feeding several electrical outlets with other devices on it).
Industrial electrical circuits may go up to 30 amps, but a single
outlet may still be only capable of 20 amps. Just to be on the safe
side, let's use 20 amps as our maximum as we do the following
calculation: A 500 watt bulb uses about 5 amps. A 1000 watt bulb
uses about 10 amps. Add up all the lights you are using and see if
you are exceeding the capacity of the circuit. Incidentally, if you
switch all the lights on at the same time, the power surge will
probably blow a fuse or circuit breaker; activate the lights one at a
time. If you are drawing a lot of power from one circuit, don't try
to operate computers or VCRs from that same circuit; the lights may
depress the voltage and may cause the computer or VCR to operate
unreliably.
8. When shooting outdoors, take advantage of reflectors; they use no
electricity and the color temperature is exactly the same as the sun.
A posterboard or a large sheet can often provide fill light to soften
shadows. This technique sometimes works inside, too.
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9. Use an amber gelled backlight if trying to chroma key talent over
a blue background. The background may reflect some blue onto the
performer making his key edges appear grainy. Amber, the opposite of
blue, counteracts the effect, creating a sharp key edge.
10. Dimming a tungsten light "reddens" its color. This effect isn't
too noticeable when people (skin tones) aren't in the picture. Also,
a 10% dimmed light still looks about normal. But as the dimming
deepens, the colors shift more. To vary lighting intensity without
affecting color, you can:
a. change bulb wattage
b. move the lighting instrument nearer or farther from the talent
c. defocus the lamp from spot to flood
d. add scrims or other diffusion material
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