Apple Final Cut Pro 6 - Manual (Page 1309)

524 Part III Color Correction and Video Quality Control
If your program has been accepted for broadcast, you can usually get a set of
guidelines specifying the broadcaster’s criteria for a legal video signal. The Corporation
for Public Broadcasting has a frequently cited set of guidelines for defining what levels
of luma and chroma are acceptable for broadcast. You will probably be in the clear with
most broadcasters if your program adheres to these guidelines, since they are fairly
conservative. Other broadcast companies publish their own guidelines.
Displaying Excess Luma and Chroma Levels
in the Viewer and Canvas
The Final Cut Pro range-checking options (in the Range Check submenu of the View
menu) allow you to enable zebra striping in the Viewer and Canvas to immediately warn
you of areas of your clip’s image that may stray outside the broadcast-legal range.
Zebra stripes appear as animated diagonal “marching lines” that are superimposed over
illegal areas in your picture or areas that are very near the broadcast-legal limits.
Additional icons are displayed to warn you about luma or chroma levels that fall
outside the legal range for broadcast.
Legal Broadcast Colors
A mistake beginners often make when creating graphics for video is to use colors
that are vivid on the computer display, but have chroma and luma levels that are
outside of the “legal” range of color that can be broadcast. Broadcasters must adhere
to these specifications or risk fines from the FCC. Therefore, if you submit a tape with
signals out of specification, it may not be accepted.
Many graphics and compositing applications have a “broadcast safe” filter that you
can use to limit the color range of a graphic so that it will be broadcast properly
without distortion. However, you should use these filters only as a last resort. It’s best
to be aware of the specifications of the video signal and keep your chroma and luma
values within proper limits.
Green zebra stripes
indicate luma from
90 to 100 percent.
Red zebra stripes indicate
luma above 100 percent.
Warning icon