Page | 299
Some more professional cameras offer full manual controls for white balance and/or black level. Use these
as instructed to ensure your camera is providing the correct white and black levels.
If you cannot make source adjustments, or can’t get it quite right by these means alone, you can use the
Brightness and Contrast controls in the Proc Amp TriCaster provides for that input to tweak black and white
levels. (Of course it is always best to perform adjustments at the source if possible.)
C.2.2 ADJUSTING COLOR
We’re going to move into color calibration next, but first we can actually use our black and white signals for
some further tests.
VECTORSCOPE
While we’re still working with black and white levels, we can introduce TriCaster’s Vectorscope, and perform
an initial test of the camera’s color balance.
A vectorscope (Figure 21-76) can be likened to the familiar ‘color wheel’ (Figure 21-77) which sweeps
radially through the colors of the spectrum – yellow, red, magenta, and so-on, around the arc of a circle.
Colors are more progressively intense (saturated) towards the outside of the circle, while color saturation is
zero at its center.
As it happens, from the vectorscope point of view, neither black nor white properly have any color saturation.
Thus with the lens cap on (or with a white card filling the viewfinder), the vectorscope should show only a
small fuzzy trace at its center. If the fuzzy dot is off-center horizontally or vertically, this would indicate that
the camera is incorrectly calibrated, actually tinting gray areas.
When the trace is off center, the direction and distance of the offset tells us what sort of tint (and how much)
is represented by the deviation. You may be able to use the color controls at your camera to correct for this
offset, or you can use the U Offset and V Offset controls in TriCaster’s Proc Amp to do so (as always, source
controls are best). Adjustments to U Offset move the trace left or right, while V Offset changes adjust its
vertical position.
Let’s move on to a slightly more rigorous testing.
To Next Page
Loading...
Need help?
General