Matte Effect is a free effect that creates a boolean bitmap. Certain effects require the usage of a hidden layer as a matte. Matte selection controls are common to such effects.
Matte Effect is offered for free, without any need for registration.
You can download the Win or Mac version. A sample project can also be downloaded.
This effect works with 8-bpc, 16-bpc, and 32-bpc color. The optimal usage will require 32-bpc and full resolution. In 32-bpc color, After Effects does not clip the video and allows the user to view any out-of-range data.


Matte Layer – A layer which will be used to isolate an object which will generate the effect.

Red Channel : Upper Limit, Lower Limit – Select a range of color values to isolate the stencil bitmap.
Green Channel : Upper Limit, Lower Limit – Select a range of color values to isolate the stencil bitmap.
Blue Channel : Upper Limit, Lower Limit – Select a range of color values to isolate the stencil bitmap.
Alpha Limit – Select limit to isolate the stencil bitmap.
Invert Bitmap – Selecting this will invert the output.