Adobe Premiere Pro CS4 - Manual (Page 385)

379 USING ADOBE PREMIERE PRO CS4
Effects and transitions
Last updated 11/6/2011
Non Red Key effect
The Non Red Key effect creates transparency from green or blue backgrounds. This key is similar to the Blue Screen
Key effect, but it also lets you blend two clips. In addition, the Non Red Key effect helps reduce fringing around the
edges of nontransparent objects. Use the Non Red Key effect to key out green screens when you need to control
blending, or when the Blue Screen Key effect doesn’t produce satisfactory results.
The following Non Red Key effect settings are adjusted in the Effect Controls panel:
Threshold Sets the levels of blue or green that determine transparent areas in the clip. Dragging the Threshold slider
to the left increases the amount of transparency. Use the Mask Only option to view the black (transparent) areas as you
move the Threshold slider.
Cutoff Sets the opacity of nontransparent areas specified by the Threshold slider. Higher values increase transparency.
Drag to the right until the opaque area reaches a satisfactory level.
Defringing Removes residual green or blue screen color from the edges of the opaque areas of a clip. Choose None to
disable defringing. Choose Green or Blue to remove a residual edge from green-screen or blue-screen footage,
respectively.
Smoothing Specifies the amount of anti-aliasing (softening) that Premiere Pro applies to the boundary between
transparent and opaque regions. Choose None to produce sharp edges, with no anti-aliasing. This option is useful
when you want to preserve sharp lines, such as those in titles. Choose Low or High to produce different amounts of
smoothing.
Mask Only Displays only the clip’s alpha channel. Black represents transparent areas, white represents opaque areas,
and gray represents partially transparent areas.
RGB Difference Key effect (Windows only)
The RGB Difference Key effect is a simpler version of the Chroma Key effect. It lets you select a range for the target
color, but you cannot blend the image or adjust transparency in grays. Use the RGB Difference Key effect for a scene
that is brightly lit and contains no shadows, or for rough cuts that don’t require fine adjustments.
For more information, see “ Difference Matte effect ” on page 377.
Note: The Difference Matte effect uses a matte to define the alpha channel much as the RGB Difference Key effect uses a
color.
The following RGB Difference Key effect settings are adjusted in the Effect Controls panel:
Color Specifies the color in the video that will be made transparent by the mask.
Similarity Broadens or reduces the range of the target color that will be made transparent. Higher values increase the
range.
Smoothing Specifies the amount of anti-aliasing (softening) that Premiere Pro applies to the boundary between
transparent and opaque regions. Choose None to produce sharp edges, with no anti-aliasing. This option is useful
when you want to preserve sharp lines, such as those in titles. Choose Low or High to produce different amounts of
smoothing.
Mask Only Displays only the clip’s alpha channel. Black represents transparent areas, white represents opaque areas,
and gray represents partially transparent areas.
Drop Shadow Adds a 50% gray, 50% opaque shadow offset 4 pixels down and to the right from the opaque areas of the
original clip image. This option works best with simple graphics such as titles.