GRASS VALLEY EDIUS VERSION 5.1 User Reference Manual page 548

Section 6 — Effects and Titles
548
Figure 638. Chromakey Rectangle Enabled
Cancel Color
Cancel Color is used to fix shadows tinted by the background. For
example, when shooting in front of a blue screen, the shadows may be
tinted blue. Cancel Color can be used to adjust the tint back to a more
neutral (gray) range.
Use the sliders or direct numeric entry to adjust the cancellation range and
power of the selected key color and its opposite in the areas where the
selected key color is bounded by other colors.
Autofit Tracking
Enable autofit tracking to adjust key color variation automatically.
CG Mode
Select this option to set the parameters for CG-generated images. This
option should not be enabled for natural images.
Soft Edge
Select this option to blur the border between the background image and the
overlaid image.
EDIUS — User Reference Guide