It may sometime happen that you render your scene with some colored background. With this kind of image there is always an issue with edge while doing pre-multiplication. Through this Gizmo you can easily deal with this kind of problem.
npremult
Updated: 4 July 2019
Author: chetalvfx
Compatible Nuke versions: 6.0 or later
Compatibility:
It may sometime happen that you render your scene with some colored background. With this kind of image there is always an issue with edge while doing pre-multiplication.
With this Gizmo you can easily deal with such kind of problem. Only you need is background color/image.
You can also find the tutorial to create or understand this Gizmo over hereTutorial on nPremultiply Gizmo
Thank You :)