Wetpixel

Using the Channel Mixer

This demo shows how to use the channel mixer to blend some green channel into the red channel. You use this technique on video that is poorly color balanced or is shot at wide angle from large distances and has a flat, green appearance. The general effect is to convert existing colors to a more natural appearance. No color is added although it may look like there is. See the final result in Quicktime or RealVideo. Although you may believe the final result has purple water, I promise it does not.

First place your clip on the timeline and select it. From the Video effects panel, find the Channel Mixer effect and add to your clip by dragging it onto the Effect Controls pane or onto the clip itself.

 

 

You should now see the channel mixer controls. The second control varies the amount of green that is mixed into the red channel. A value of 20-50 generally does what you want. Remember that you should color balance after doing this, so be conservative.

 

 

I'm going to set the control to 45 here. You can see how dramatically this effects the video. In the real case I might use less since I would follow up with careful color balancing, but this does well for the demo. For this clip I am also going to use the "Green-Const" control to remove a small amount of green from the entire image.

 

 

I will set the green constant control to -3. A little goes a long way. What this does is change the color of "black" to remove the green cast. You can see the effect is to make the video look less dirty.

 

 

That is it for this demo. The values I chose are representative of what you would use but I spent very little choosing them. In a real application I would expect the result to be better than this.