Adobe AFTER EFFECTS 7.0 - Minimax Effect; Remove Color Matting Effect

ADOBE AFTER EFFECTS 7.0
User Guide
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Minimax effect
The Minimax effect enlarges or reduces a matte for a specific channel or all channels. It assigns each pixel the
minimum or maximum pixel value found within a specified radius. For example, a white solid layer with a square
mask shrinks one pixel on each side using Minimum and a radius of 1. The layer’s quality setting does not affect
Minimax.
This effect works with 8-bpc and 16-bpc color.
Original (left); effect applied to layer created from solid with Fractal Noise effect (center); result (right)
Adjust the following controls for the Minimax effect:
Operation Specifies how the effect processes the matte. Minimum replaces a pixel with the smallest pixel value
within the radius specified, and Maximum replaces a pixel with the largest pixel value within the radius specified.
Minimum Then Maximum performs the Minimum operation on the layer followed by the Maximum operation
using the Radius setting, and Maximum Then Minimum does the opposite.
Radius Specifies how many pixels to examine for the Minimum or Maximum operation.
Channel Specifies the channel. Color affects the color channels only. Alpha and Color affects all channels. Red,
Green, Blue, and Alpha affect only the respective channels.
Direction Specifies the direction of scanning for values. Horizontal & Vertical scans all directions for the minimum
or maximum pixel. Just Horizontal and Just Vertical scan only left and right or up and down, respectively.
Remove Color Matting effect
The Remove Color Matting effect removes color fringes from layers that are premultiplied with a color. It is useful
when merging alpha and fill 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. Halos can also be caused by a misinterpretation of an alpha channel’s premultiplied color.
Use Background Color to specify the new background color when you want to change the color of a matte.
This effect works with 8-bpc and 16-bpc color.
Original (left), after applying the Remove Color Matting effect (right)
Use this effect in conjunction with other effects that let you create alpha channels, to achieve more control over the
appearance of the alpha channel.