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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 black-
and-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.
