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Broadcast Pix
V8.5
4.7.2 Chromakey Settings
There are a number of Chromakey settings that may be adjusted to give you greater
control of your Chromakey. It is important to note that the smallest adjustment can
cause a key to look good or bad. All adjustments are controlled though the Key’s
[Chrma Cntrls]
PixPad, as shown on the previous page.
When creating a Chromakey it is all about creating a wedge of color on the color
wheel to generate a matte.
Each Chromakey has these available controls, although Hue and Acceptance Angle
are the most important:
Hue
[Hu]
: Position around color wheel of the wedge, the actual color of the
Chromakey background. Red = 0 (approximately), Green = 120, Blue = 240
Gain
[Gain]
: Increases the transparency of the key. It can tighten the key around an
object at the cost of making the edges harder. (0 to 100)
Acceptance Angle
[AcAn]
: Size of the wedge on the color wheel, in degrees. Outside
of the acceptance angle is opaque, within has increasing transparency as you
approach the exact hue. The wider the angle the more colors are accepted as
transparent. (0 to 180)
Clip
[Clp]:
Represents offset of the wedge of the color being selected. Negative (-)
towards higher saturation, positive (+) towards opposite side of the color wheel. Useful
when dark objects are becoming fully transparent from a small amount of reflected
green. (-100 to 100)
Shrink
[Shr]
: Shrinks the key around the object based on the shape of the
object. Good for tightening the key around hair. If it is overdone it can also give a
harsh edge. Useful as a finishing step, but won’t help if there is not a good set of base
parameters. (0 to 100)
Spill Suppression
[Spil]
: Spill suppression subtracts a color value from places from the
!
Chromakey source where the matte is not totally opaque or transparent. So instead of
a green fringe, there is a black one, for example. (0 to 100)
Suppression Angle
[SuAn]
: A 2nd wedge that can be generated that has a hard edge
instead of the soft edge. (0 to 180)
Suppression Clip
[SCl]
: Same as Clip, but for a hard edge mask. (-100 to -5)
4.7.2