Grass Valley Kayak HD v.6.9.3 - Manual (Page 381)

Kayak — User Manual 381
Chroma Key Operating Notes
Key Controls
The purpose in adjusting Clip Hi and Clip Low is to cause the proper hole to
be cut in the background. All areas of the backing color should be full back-
ground while all areas of the foreground should make the background
completely invisible. The easiest way to do this is to observe the key signal
while making your adjustments.
The smaller the difference between Clip Hi and Clip Low , the higher the keyer
gain. High gain amplifies noise present in the transition between trans-
parent and opaque. The correct setting is with
Clip Hi and Clip Low set to just
barely achieve opacity and transparency, respectively.
1. Touch the Key Controls data pads to activate these controls.
Data Pad 1 contains Clip Hi / Clip Low / Opacity.
Data Pad 2 contains Size and Position.
You can now manually adjust keyer clipping controls.
2. Press the Key PVW button on the Main control panel and look at the
preview output on a picture and waveform monitor.
Figure 303. Key Controls, Part1, Clip HI, Clip Low, Opacity
3. Adjust Clip Hi so that all areas of the foreground objects are white. If Clip
Hi is set too low (too far clockwise), much of the translucent areas will
be forced to be fully opaque, hardening the key and darkening the
transition area between background and foreground.