UnMult

Free! Remove black to add an alpha channel to a lighting effect

Description

The UnMult plug-in generates an alpha channel for a lighting effect, allowing it to be applied to your footage using the Normal transfer mode in After Effects or another program. It does this by un-premultiplying the RGB to reach full saturation and then attenuating the alpha by the same amount.

UnMult assumes your lighting effect (a lens flare, for example) is applied to a black solid with a fully opaque alpha channel. After applying UnMult, the lighting effect may appear unchanged, but the pixel values will have been modified to use a semi-transparent alpha.

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Version History

1.2 -

Aug 27, 2025

First version posted to aescripts

Compatibility

After Effects

2025, 2024, 2023, 2022, 2021

Media Encoder

2025, 2024, 2023, 2022, 2021

Premiere Pro

2025, 2024, 2023, 2022, 2021