CHAPTER 8
266
Superimposing and Compositing with Transparency
Smoothing
Specifies the amount of anti-aliasing that Premiere applies to the boundary
between transparent and opaque regions. Anti-aliasing blends pixels to produce softer,
smoother edges. Choose None to produce sharp edges, with no anti-aliasing. This is useful
when you want to preserve sharp lines, such as those in titles. Choose Low or High to
produce different amounts of smoothing.
Using the RGB Difference key
The RGB Difference key is a simpler version of the Chroma key. You can select a range
of 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. Select a key color by clicking the color swatch or by
using the eyedropper to choose a color from the thumbnail beneath the color swatch.
Similarity
Broadens or reduces the range of color that will be made transparent. Higher
values increase the range.
Smoothing
Specifies the amount of anti-aliasing (softening) that Premiere applies to the
boundary between transparent and opaque regions. Choose None to produce sharp edges,
with no anti-aliasing. This is useful when you want to preserve sharp lines, such as those
in titles. Choose Low or High to produce different amounts of smoothing.
Using the Blue Screen and Green Screen keys
The Blue Screen and Green Screen keys create transparency from true chroma blue and
true chroma green. Use these keys to key out well-lit blue or green screens when creating
composites.
Threshold
Drag to the left until the blue or green screen is made transparent.
Cutoff
Drag to the right until the opaque area reaches a satisfactory level.
To fine-tune edges, drag Threshold and Cutoff sliders in small amounts.
c00.book for PS Page 266 Tuesday, March 31, 1998 1:28 PM
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