Apple Color 1.5 - Manual (Page 405)

When using analog devices, make sure they are calibrated for accurate brightness and
color so you can color correct your video accurately.
This appendix covers the following:
• About Color Bars (p. 405)
• Calibrating Video Monitors with Color Bars (p. 405)
About Color Bars
Color bars are an electronically generated video signal that meet very strict specifications.
Because the luma and chroma levels are standardized, you can use color bars passing
through different components of a video system to see how each device is affecting the
signal.
NTSC and PAL each have specific color bar standards, and even within NTSC and PAL
there are several standards. When you evaluate color bars on a video scope, it is important
to know which color bars standard you are measuring, or you may make improper
adjustments. “SMPTE bars” is a commonly used standard.
When Should You Use Color Bars?
Analog devices always need to be calibrated and adjusted, even if only by minute
degrees. This is because heat, age, noise, cable length, and many other factors subtly
affect the voltage of an analog electronic video signal, which affects the brightness and
color of the video image. Color bars provide a reference signal you can use to calibrate
the output levels of an analog device.
Calibrating Video Monitors with Color Bars
Editors and broadcast designers shouldn’t rely on an uncalibrated monitor when making
crucial adjustments to the color and brightness of their programs. Instead, it’s important
to use a calibrated broadcast monitor to ensure that any adjustments made to exposure
and color quality are accurate.
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Calibrating Your Monitor
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