EyeonTips:Manual/Fusion 6/Matte Control
From VFXPedia
Despill Math
In literature and tutorials you will encounter formulas to despill blue and green screens that can be implemented using a custom tool or channel booleans. The most common formulas, however, are already implemented in Fusion's matte tools:
- Rare: limits green or blue to the maximum of the other two channels: g = min(g , max(r, b))
- Medium: the exact formula is unknown but it seems like it limits a channel to the average of the other two only if it is larger than the maximum of the other two. This often creates a visible fringe in the middle of the despilled area.
- Well-Done: limits green or blue to the average of the other two channels: g = min(g, (r + b) / 2)
- Burnt: limits green or blue to the smaller one of the other two channels: g = min(g, min(r, b))
