Grass Valley Zodiak v.6.0 Mar 15 2006 - Manual (Page 333)

Zodiak — User Manual 333
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ponent is not turned on, it is still possible to adjust its color correction
values, but they are not applied to the video. When a component is not
turned on, the scope trace for the component is made a darker shade of
green to further indicate that the transfer function is not being applied to
the video. To show that the color corrector for a component is turned off
and passing signals at unity gain, a unity trace will appear over the top of
a darker scope trace. In
Figure 234 , the Green component is not turned on,
so it is showing two traces, a dark green and a unity trace; the Red and
Green components are on showing a single trace. The scope traces change
shape to show the transfer function that would be applied if the compo-
nent's color correction processor were turned on.
The oscilloscope for each color component is modeled after a waveform
monitor into which a black to white video luminance ramp is fed after
being subjected to the color corrector modifications. The waveform
monitor is set up to show red, green, and blue components. In a more
abstract sense, the horizontal scale of the graph corresponds to the input
color component intensity level to the color corrector, and the vertical scale
corresponds to the output level from the color corrector. Nominally, the
diagonal line in the figure is the unity trace, and it starts at the black level
in the lower left and it ramps linearly to the white level at upper right. The
dotted graticule lines signify nominal black to white range. The solid grat-
icule lines mark the absolute limits of the graph.
The slope of the diagonal line is proportional to the component's gain. At
gain zero, the line is flat and level. If the gain is adjusted high enough so
that the trace would exceed the absolute vertical limits of the graph, the
trace is modified to look as it would if the ramp signal were clipped by the
limiters in the actual color corrector.
Component Lift (black level) is signified by moving the trace up and down
without changing its slope. Component lift is the y-intercept, the b in y =
mx + b, if the diagonal line were not limited as described above. The ver-
tical scale is such that zero is at the black dotted line, 100 IRE is at the white
dotted line.
Component Gamma is represented as curvature in the line. Gamma is an
exponential function applied to the input such that the concavity of the
curve is downward for positive gamma and upward for negative. At zero
gamma, the trace is a straight line.
The Changes on (Red/Green/Blue) Also Apply to pane has two on/off buttons. The
pane title and the button labels are dependent on the selection of the color
component in the Color Corrector Transfer Function pane. If the user
selects Blue as the color to be adjusted, as is shown in
Figure 234 , the title
of the pane is, Changes on Blue Also Apply to , and the two buttons are Red and
Green . When these buttons are active, the adjustments applied to the origi-
nally selected color component is also applied to the one(s) selected in the
pane. For example, if the user chooses to adjust Blue and selects Red in the
Changes on Blue Also Apply to pane, then any adjustments to Blue's
Gamma value will be applied to Red's Gamma value. The Red oscillo-