Adobe Premiere Pro CS4 - Manual (Page 386)

380 USING ADOBE PREMIERE PRO CS4
Effects and transitions
Last updated 11/6/2011
Remove Matte effect
The Remove Matte effect removes color fringes from clips that are premultiplied with a color. It is useful when
combining alpha channels with fill textures from separate files. If you import footage with a premultiplied alpha
channel, or if you create alpha channels with After Effects, you may need to remove halos from an image. Halos are
caused by a large contrast between the image's color and the background, or matte, color. Removing or changing the
color of the matte can remove the halos.
Use Background Color to specify the new background color when you want to change the color of a matte.
Track Matte Key effect
(32-bit) The Track Matte Key effect creates transparent areas in a clip that correspond to the luminance levels of
another clip. Transparent areas reveal the image produced by clips in lower tracks. Exclude the matte clip from the
output by selecting the clip and choosing Clip > Enable.
Jeff Schell provides a video tutorial about the Track Matte Key effect on the Digital Producer Magazine website .
More Help topics
“ Move or change the transparent area with Track Matte Key ” on page 423
“ Compositing clips ” on page 415
Noise & Grain effects
Dust & Scratches effect
The Dust & Scratches effect reduces noise and defects by changing dissimilar pixels within a specified radius to be more
like their neighboring pixels. To achieve a balance between sharpness of the image and hiding defects, try various
combinations of radius and threshold settings.
Original image with scratches (left), enlarged view of scratches (center), and scratches removed with loss of clarity (right)
Radius How far the effect searches for differences among pixels. High values make the image blurry. Use the smallest
value that eliminates the defects.
Threshold How different pixels can be from their neighbors without being changed by the effect. Use the highest value
that eliminates the defects.
Median effect
The Median effect replaces each pixel with a pixel that has the median color value of neighboring pixels with the
specified Radius. At low Radius values, this effect is useful for reducing some types of noise. At higher Radius values,
this effect gives an image a painterly appearance.