How to Use Knoll Unmult Cs6 for Creating Alpha Channels from Black Backgrounds
Knoll Unmult Cs6 is a free plug-in from Red Giant Software that allows you to create an alpha channel from any image or video shot on a black background. This is especially useful for generating alpha channels for flares, clouds, water droplets, and other effects that are rendered or filmed on black. In this article, we will show you how to use Knoll Unmult Cs6 in Adobe After Effects to create stunning composites and motion graphics.
What is Knoll Unmult Cs6
Knoll Unmult Cs6 is a plug-in that was originally developed by John Knoll, one of the creators of Photoshop and a visual effects supervisor at Industrial Light & Magic. It was later acquired by Red Giant Software and made available for free on their website[^1^]. Knoll Unmult Cs6 works in After Effects CS3, CS4, and CS5 (64-bit) and can be downloaded from here.
How does Knoll Unmult Cs6 work
Knoll Unmult Cs6 works by analyzing the luminance values of an image or video and creating an alpha channel based on the darkest pixels. This means that any pixel that is pure black will become transparent, while any pixel that is not black will become opaque. This way, you can easily isolate the elements that are shot on black from the background and composite them over other footage or images.
How to use Knoll Unmult Cs6 in After Effects
To use Knoll Unmult Cs6 in After Effects, follow these steps:
Import your footage or image that is shot on black into After Effects.
Create a new composition and drag your footage or image onto the timeline.
Apply the Knoll Unmult Cs6 effect to your layer. You can find it under Effect > Red Giant > Knoll Unmult.
Adjust the Threshold parameter if needed. The Threshold determines how dark a pixel has to be to become transparent. A lower value will make more pixels transparent, while a higher value will make more pixels opaque. You can use the preview window to see how the effect affects your layer.
Add any other effects or adjustments to your layer as desired.
Composite your layer over another footage or image using the blending modes or masks.
Here is an example of using Knoll Unmult Cs6 to create an alpha channel for a flare rendered on black:
![Flare before and after applying Knoll Unmult Cs6](https://i.imgur.com/0ZQX9yF.png)
Tips and tricks for using Knoll Unmult Cs6
If your footage or image has some noise or grain in the black areas, you can use the Noise Reduction parameter to smooth out the alpha channel. A higher value will reduce more noise, but may also remove some details from your layer.
If your footage or image has some color spill or tint in the black areas, you can use the Color Correction parameter to remove it. A higher value will desaturate more color, but may also affect the brightness of your layer.
If you want to invert the alpha channel created by Knoll Unmult Cs6, you can use the Invert parameter. This will make the black pixels opaque and the non-black pixels transparent. This can be useful for creating mattes or masks from white backgrounds.
If you want to learn more about how to use Knoll Unmult Cs6 for creating alpha channels from black backgrounds, you can watch this video tutorial by Red Giant[^2^] or this forum post by Creative COW[^3^].
Knoll Unmult Cs6 is a free and easy-to-use plug-in that can help you create alpha channels from black backgrounds in After Effects. It can save you time and effort when working with flares, clouds, water droplets, and other effects that are rendered or filmed on black 061ffe29dd