Trancparency & Color in Fusion

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

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