Grass Valley DD10 part 1 - Manual (Page 40)

2.7 Keyers Diamond digital DD10
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2.7.6 AUTO KEY ADJUSTMENT
Auto key effects different automatic functions in the different key modes.
Add Key switches the key control to 1:1 transmission in order that key signals. e.g.
from the caption generator have an unchanged effect.
Luminance Key adjusts Clip and Gain in such a way that the key signal is just swit-
ched through.
For Chroma Key see the section Automatic Chroma Key Adjustment.
Note: After termination of all automatic key adjustments, the corresponding pa-
rameters can still be changes manually.
2.7.7 CHROMA KEY
Press Chr Key in the Keyers panel to select Chroma Key mode. In DynaChrome
Key mode, the foreground signal is proportionally and subtractively deprived by the
key color in the key color area and colored neighbouring areas. The result is a
cleaned key fill signal which now contains in key color areas shadow-free black and
in neigh-bouring areas the de-mixed foreground colors.
The key control signal is also derived from the foreground signal. The key control
signal is multiplied with the background signal. The cleaned key fill signal and the
multiplied background signal are added. This method ensures that all details are
reproduced true to the original in the area of the key color.
FGD Fade The FGD Fade (foreground fade) key switches over the chroma key procedure.
Now, the cleaned key fill signal and the background signal are faded in one fading
operation by the key control signal. In the area of the key color, only chrominance
is subtractively removed, luminance is retained. However, this will impair some ad-
vantages of the DynaChrom procedure (good reproduction of details and transpa-
rency).
For optimal adaptation of cross fadings on edges or for optimization in case of
transparencies between foreground and background, the luminance value can be
adjusted in the area of the key color.
Adjustment is made with the Luminance control. During adjustment, Key color
has to be held down.
This mode is recommendable when object edges will show unnatural, extreme
brightenings in details and transparency areas in case of too intense CLEAN–UP
adjustment, or extreme darkenings in case of too intense DENSITY adjustment.
For optimal adaptation of fade transitions at edges or for optimization in case of
transparencies between foreground and background, the luminance value can be
adjusted in the area of the key color transitions. Adjustment is made with the func-
tion LUMOFS (Luminance Offset). During adjustment, the Key Color key has to
be held down and the Luminance control be operated.
Chr Key