In order to faithfully digitize or reproduce video, postproduction and duplication facilities
use hardware devices called
waveform monitors
and
vectorscopes.
Similarly, you can use
the Adobe Premiere Pro software vectorscope and waveform monitor to accurately
evaluate video
levels
—specifically, color and brightness. These instruments not only help
you output a video program that meets broadcast standards but also assist you in making
adjustments based on aesthetic considerations, such as color corrections.
A C
B
Using Help | Contents | Index Back 111
Adobe Premiere Pro Help Assembling a Sequence
Using Help | Contents | Index Back 111
A waveform monitor is useful in measuring the brightness, or
luminance
component, of a
video signal. The waveform monitor works something like a graph. The horizontal axis of
the monitor corresponds to the video image. Vertically, the waveform measures
luminance, in units called
IRE
(named for the Institute of Radio Engineers). Bright objects
produce a waveform pattern (bright green areas) near the top of the graph; darker objects
produce a waveform toward the bottom. For NTSC video in the United States, luminance
levels should range from 7.5 to 100 IRE. Japan’s implementation of NTSC standards
permits a luminance range from 0 to 100 IRE.
A vectorscope measures the
chrominance
, or color components, of a video signal,
including
hue
and
saturation
. A vectorscope maps a video’s color information onto a
circular chart. Saturation is measured from the center of the chart outward. Saturated,
vivid colors produce a pattern some distance from the center of the chart, while a
blackand-
white image produces only a dot at the center of the chart. The particular color, or
hue, of the image determines the angle of the pattern. Small boxes indicate where fully
saturated magenta, blue, cyan, green, yellow, and red (present in a color bars test pattern)
should appear. In NTSC video, chrominance levels should never exceed these target
areas.
You can use a number of video effects to adjust the video levels. See “Working with
Standard effects” on page 244 for a full explanation.
Using a reference monitor
In certain circumstances, it can be useful to compare different frames of a sequence side
by side, or to view the same frame of a sequence using different viewing modes. You can
do this by opening a reference monitor, which acts much like a secondary Program view.
Using Help | Contents | Index Back 112
Adobe Premiere Pro Help Assembling a Sequence
Using Help | Contents | Index Back 112
You can cue the frame of a sequence displayed in the reference monitor independently
from the Program view. This way, you can cue each view to a different frame for
comparison—to use the color matching filter, for example. Alternatively, you can
gang
the
reference monitor and Program view together, so that they both show the same frame of a
sequence, and move in tandem. This is especially useful for color correcting tasks. By
setting the reference monitor’s viewing mode to a waveform monitor or vectorscope, you
can make adjustments to the color corrector or any other video filter more effectively.
For more about using the color matching filter or color correction filter, see “Using the
Color Match effect” on page 256.
Using a reference monitor to aid in color correction
A reference monitor opens as a separate window, though you can save screen space by
dragging its tab into the Source view of the Project window. You can specify the reference
monitor’s quality setting, magnification, and viewing mode just as you would in the
Monitor window. Its time ruler and viewing area bar also work the same. But because it’s
