The Remove Transparency effect negates transparent values in an image. You can use the Remove Transparency node to remove the result of antialiasing around an image.
Remove Transparency Properties
|Name||Lets you rename the node.|
All values above the Threshold represent a transparent value. In this field, you must identify the value above which all alpha values are considered transparent. Alpha is measured from 0 to 255.
|Remove Colour Transparency||
Determines which pixels in the Colour-Art (RGB channels) to make fully opaque or fully transparent.
|Remove Alpha Transparency||
When selected, the Threshold value is used to determine which pixels in the alpha channel to make fully opaque or fully transparent.