Adobe Premiere Elements 12 - Manual (Page 168)

Threshold
Cutoff
Smoothing
Mask Only
Similarity
Blend
Threshold
Cutoff
Smoothing
Mask Only
Sets the level of blue or green that determines 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.
Sets the opacity of the nontransparent areas that the Threshold setting specifies. Dragging the Cutoff value to the right increases the
opacity. Select the Mask Only option to view the white (opaque) areas as you drag the Cutoff value.
Specifies the amount of anti-aliasing (softening) applied 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.
Displays only the clip’s alpha channel. Black represents transparent areas, white represents opaque areas, and gray represents
partially transparent areas.
Chroma Key (Windows only)
The Chroma Key effect creates transparency from a color or range of colors. You can use this key for a scene shot against a screen that contains
a range of one color, such as a shadowy blue screen. Select a key color by clicking the Color swatch or by clicking the Eyedropper tool and
selecting a color in the Monitor panel. Control the range of transparent colors by adjusting the tolerance level. You can also feather the edges of
the transparent area to create a smooth transition between the transparent and opaque areas.
Chroma Key
A. Original clip B. Blue color keyed out C. Clip on second track D. Final composite clip
Apply the Chroma Key effect to a clip multiple times to key out multiple colors.
Adjust the following Chroma key settings as needed:
Broadens or reduces the range of color that will be made transparent. Higher values increase the range.
Blends the clip you are keying out with the underlying clip. Higher values blend more of the clip.
Controls the amount of shadows in the range of color you keyed out. Higher values retain more shadows.
Darkens or lightens shadows. Drag to the right to darken shadows, but do not drag beyond the Threshold slider; doing so inverts gray and
transparent pixels.
Specifies the amount of anti-aliasing applied 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 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, as modified by the key settings. If Mask Only is selected, opaque areas of a clip appear white,
transparent areas appear black, and partially transparent areas appear gray. Remove all the gray areas to produce a clean, hard-edged key.
Difference Matte effect
The Difference Matte effect creates transparency by comparing a source clip with a difference clip, and then keying out pixels in the source image
that match both the position and color in the difference image. Typically, it’s used to key out a static background behind a moving object, which is
then placed on a different background. Often the difference clip is simply a frame of background footage (before the moving object has entered the
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