Apple Final Cut Pro 6 - Manual (Page 1325)

540 Part III Color Correction and Video Quality Control
The Flesh Tone line is only meant to be an approximation; it’s more important that the
shot look correct than that it fit this line exactly.
Using Color Bars for Video Calibration
When using analog devices, make sure they are calibrated for accurate brightness and
color so there’s no distortion when you capture and color correct your video.
About Color Bars
Color bars are electronically generated video signals 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. For example, suppose you record color bars that have a 100 percent white
level in a camcorder and then play the videotape back on a VTR. If the white level
output from the VTR is only 90 percent, you know that you need to increase the luma
level output of the VTR.
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 bar standard you are measuring, or you may make
improper adjustments. “SMPTE bars” is a commonly used standard.
The Flesh Tone
line is here on
the Vectorscope.
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.