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 Founder and Lead Educator of DVResolve.com and is Blackmagic Design Certified Master Trainer. He’s edited commercials for major brands and has done color & VFX for independent films. He consults on post-production workflow and creating online education. Gedaly is the co-founder of Working.Actor, a former marketing manager for large brands, and creates original film projects with his production company Razee.