Adobe 65021048 User Manual page 377

See also
"Chroma Key effect" on page 335
About RGB Difference Key
The RGB Difference Key is a simpler version of the Chroma Key. 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 for a scene that is brightly
lit and contains no shadows, or for rough cuts that don't require fine adjustments.
Note: The Difference Matte uses a matte to define the alpha channel much as the RGB Difference Key uses a color.
The following RGB Difference Key settings are adjusted in the Effect Controls panel:
Specifies the color in the video that will be made transparent by the mask.
Color
Broadens or reduces the range of the target color that will be made transparent. Higher values increase
Similarity
the range.
Specifies the amount of anti-aliasing (softening) that Adobe Premiere Pro applies to the boundary
Smoothing
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.
Displays only the clip's alpha channel. Black represents transparent areas, white represents opaque
Mask Only
areas, and gray represents partially transparent areas.
Adds a 50% gray, 50% opaque shadow offset 4 pixels down and to the right from the opaque areas of
Drop Shadow
the original clip image. This option works best with simple graphics such as titles.
See also
"RGB Difference Key effect" on page 338
About Blue Screen Key
The Blue Screen Key creates transparency from true chroma blue. Use this key to key out well-lit blue screens when
creating composites.
The following Blue Screen Key settings are adjusted in the Effect Controls panel:
Sets the levels of blue that determines transparent areas in a clip. Dragging the slider to the left increases
Threshold
the amount of transparency. Use the Mask Only option to view black (transparent) areas as you drag the Threshold
slider.
Sets the opacity of nontransparent areas specified by the Threshold setting. Dragging the Cutoff slider to the
Cutoff
right increases the opacity. Use the Mask Only option to view white (opaque) areas as you drag the Cutoff slider.
Specifies the amount of anti-aliasing (softening) applied to the boundary between transparent and
Smoothing
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.
Displays only the clip's alpha channel. Black represents transparent areas, white represents opaque
Mask Only
areas, and gray represents partially transparent areas.
April 1, 2008
ADOBE PREMIERE PRO CS3 371
User Guide