Ross Synergy 100 MD, Operator'S Manual

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Synergy 100 MD Operator’s Manual (v7.2 MD-S100) Keying • 7–31
• If you only have access to Key type lights, you can simulate the effect of fill lights by
bouncing a Key light off of a reflector and then on to the Chroma Key background. Also,
you can use diffused glass, gels, or scrims to soften the light from a Key light. If you use
any of these methods it’s important to note that you will lose a significant amount of the
original light intensity. Therefore, it takes more lights to reach the optimum IRE level
required for a good Chroma Key.
Lighting the Foreground (Talent)
• You can maximize the quality of your Chroma Key if you separate the foreground
(talent) from the background by 6 – 8 feet. This enables you to light the foreground and
the background separately, thus reducing or avoiding “spill” and/or shadows.
Separation also allows you more flexibility in how you light your talent. You may still
choose to use a flat lighting technique, but with separation, the option exists to light your
talent using a more dramatic 3-light, “Rembrandt style of lighting”, typically used in
other lighting applications. This style is characterized by three lights – a Key, a fill, and
a back light.
• If spill does occur between the background and the foreground, a blue “halo” or “matte
line” appears around the talent’s shoulders and hair. This can be reduced or eliminated
by using a yellow, straw, or amber colored light for the talent’s back light. It will wash
out or neutralize the blue reflection from the background on the back of the talent.
• As a general rule, it is good practice to light the foreground and the background to
approximately the same IRE levels but this is often varied when dramatic lighting effects
are required for the talent.
• And finally, be careful not to mix lights with different color temperatures on the same set
(either foreground or background). The human eye and brain are able to deal with the
subtle differences in color temperatures but cameras are not nearly that smart. If you
must use lights with different color temperatures, make sure you use colored gels to
compensate for the differences. Otherwise, you may experience holes in your Chroma
Key that will be very difficult to remove.
Additional Chroma Key Tips and Considerations
Along with lighting, there are a number of other studio elements that should be taken into account
when setting up your Chroma Keys. They include, the background material itself, the camera and its
setup, Keying from a prerecorded signal on VTR, and using compressed video sources.
• Green and blue are the two most common colors used for chroma Keying backgrounds
and are equally effective. Blue was initially chosen because it is the complimentary
color to flesh tone and, therefore, the easiest to Key out (we don’t want to Key out the
faces, do we …). Given today’s technology, almost any color can be used but blue and
green are still the most widely used.
• There are a number of different materials commonly used as Chroma Key backgrounds
and each has its benefits. The most common are paper, fabric, and paint. Paper is not as
durable but can be more cost effective and more easily set up than the other two. Paint
takes time and must be applied in several coats to ensure a deep, complete covering,
while fabric also takes time and must be mounted and hung properly. Contact your
television set and lighting distributor for details on the material that best meets your
budget and application.
• If you are creating your Chroma Key on a studio set, it is generally accepted that the
quality of your Chroma Key is directly related to the quality of the camera shooting the
scene. The background video can come from any number of sources and may be quite