Knoll Unmult -

| Method | Pros | Cons | | :--- | :--- | :--- | | | Fastest, no rendering. | Doesn't create an Alpha channel. Reds get washed out. You can't apply Layer Styles or Drop Shadows. | | Luma Key | Native to AE. | Destructive to soft edges (feathers). Removes white from the graphic itself if the graphic is bright. Slow to fine-tune. | | Extract Effect | Good for controlled luma ranges. | Complex to set up; requires multiple masks often. | | Knoll Unmult | One click. Preserves color. Creates true Alpha. Works on grainy footage. | Requires a 3rd party plugin (Red Giant). |

If you don't want to install a plugin, you can recreate the Knoll Unmult logic using built-in After Effects tools: knoll unmult

Unmult makes the core of the effect (like the center of a flame) opaque, whereas blend modes always keep the layer semi-transparent relative to what is behind it. How to Get and Use Knoll Unmult | Method | Pros | Cons | |

Unmult is dramatically faster and yields higher quality results than Luma Key or Extract for 99% of black/white background scenarios. You can't apply Layer Styles or Drop Shadows