Performing A Chroma Key; Identify Key-Colors - Videonics MX-1 Instruction Manual

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particularly good for chroma key experimentation because lighting is
simpler to control.
• Be sure no other portion of the image shares the key color (the color of
background that will be keyed out). The MX-1 can chroma key on any
color, so you can select a background color based on your subject. Bright
blue or green are the colors most commonly used in professional chroma
key studios.
• Use even lighting on the background, to eliminate hot-spots and shadows.
Lights coming from the camera's direction tend to reflect off the back-
ground, creating glare. Multiple lights coming from several directions are
particularly good as they tend to fill in the shadows.
• Allow enough room between the subject and the chroma key backdrop to
allow you to light the subject without casting shadows or excess light on
the backdrop.
• Use non-reflective background material.
• Reflectors are an inexpensive and flexible way to bring in light from other
directions, especially in outdoor lighting.

Performing a Chroma Key

In the following steps, assume that source A is the foreground source —
the picture with the solid color backdrop that will be replaced. In the previ-
ous example, that would be our superhero. Source B is the background
picture — the city, in the example.
Select Sources
The first step is to determine which sources to use for the chroma key:
• Use the appropriate CUT button to choose the background image. In this
example, you would press the CUT B button to choose the footage of the
city. This source will appear on the OUTPUT monitor.
• Use the ABCD buttons to set the NEXT source to be the foreground source.
In this case, you would press A to choose the image of the superhero on
the chroma key backdrop.

Identify Key-Colors

The next step is to identify the range of colors that will be replaced. You
can chroma key on any color in the foreground scene.
• Press the CHROMA KEY button. The normal PREVIEW screen will be
replaced by a full-screen image of source A (the superhero). A small,
flashing cross (called a "cursor") will appear on the image.
• Use the arrow keys to position the cursor over an area that contains the
chroma key color (the color of the chroma key background).
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