If you spend a lot of time in Fusion, you may have noticed the “Pre-Divide/Post-Multiply” checkbox on many tools…
But what does it do?
Compositing is all a about math. Sometimes operations don’t get applied to just the part of the image you want.
You may apply a color corrector to a node that has transparency, but the effect ends up applying to multiple layers.
Pre-Divide/Post-Multiply is the solution!
In this video from VFX Study, you’ll learn about:
- 01:08 Color and Alpha Examples
- 04:50 Unpremultiplied Images and Manual Workflow
- 15:26 Numerical Example
Gedaly is the Managing Editor of DVresolve.com. He is a professional editor, having cut national commercials for major companies, and does color & VFX for indie films at Mask & Feather. He’s also a filmmaker, writing and directing shorts & features. Gedaly is the co-founder of Working.Actor and former marketing strategist for large brands.