Tektronix Grass Valley 3000 - Manual (Page 174)

4-36
Section 4— Switcher Operations
2. Select the source to be use as the foreground signal on that
Keyer and select Chroma Key mode.
3. Select a neutral gray as the initial background signal.
These adjustments can either be made manually or via an
automatic setup mechanism. To use the Auto Setup continue with
the following text; to use the Manual Adjustment procedure refer
to
page 4-37 .
NOTE: All knobs on the Switcher panel incorporate acceleration logic,
that means the *speed* you turn a knob affects the amount a parameter
is modified for the same *rotation*. For example, if a knob is rotated
slowly in one direction then rapidly returned to the original position,
chances are the value of the parameter will NOT be the same as the initial
value. Therefore, it is necessary to make all adjustments slowly to stay
under the acceleration threshold. Failure to do so can make your Chroma
Keyer setup difficult.
Auto Setup
An automatic setup mechanism is available to rough-in the
Chroma Key. In some cases with well-designed chroma key studio
sets, the auto setup produces a usable key with no further
adjustments. However, additional manual adjustments made
after the auto setup can almost always improve the key.
To use Auto Setup:
1. Select CHR KEY/SETUP/AUTO SETUP in the menus. (The
Model 4000-2A panel also provides an AUTO SETUP button on
the panel.) A cursor displays on the keyer's output. Use the
wipe positioner to position the cursor over a portion of the
background to be keyed. (If lighting variations exist, try the
Auto Setup at different cursor locations.)
2. Press the AUTO SETUP menu (or panel button a second time)
to initiate the setup. When setup sequence completes, the
cursor disappears and a partially set up key appears.