Apple Final Cut Pro 5 - Manual (Page 1305)

518 Part III Output
Choosing Gamma Correction Options in Final Cut Pro
If your computer’s graphics card supports gamma correction, Final Cut Pro uses the
card automatically for accurate gamma correction. If your computer has an older
graphics card that does not support gamma correction, you have you two options:
 Accurate: High-quality gamma correction. This option is the most accurate, but also
requires the most CPU power.
 Approximate: Lower-quality gamma correction. This option leaves more processing
power available for real-time effects, but results in less accurate color and
brightness rendition.
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Tip: If your real-time performance is limited, try changing the gamma correction
setting to Approximate (if available).
To choose a gamma-correction option in the current sequence:
1 Open a sequence in the Timeline.
2 Choose Final Cut Pro > System Settings, then click the Playback Control tab.
3 Choose Accurate or Approximate from the Gamma Correction pop-up menu.
More About Gamma Correction
When a video signal is displayed on a monitor, the amount of brightness by which a
pixel is altered depends on the original strength of the incoming signal. A gamma
curve describes how the brightness of an incoming video signal (shown on the x axis)
is translated to the brightness of the displayed signal.
In most displays, the darkest and brightest parts of a signal remain relatively
unchanged from the incoming signal to the displayed signal, so the gamma curve is
linear at those points. The incoming midrange (gray) values are darkened in varying
amounts on the display, so the graph shows a curve.