The After Effects Illusionist, 2nd Edition

5The Channel Effects

The Channel effects category is difficult to define. All of the effects here deal with the channels in a layer—red, green, blur, and alpha. All of the effects here allow you to change or blend levels together, often with the channels of other layers. This is an effects category filled with both advanced and obsolete effects, and the practical usage of them is not always obvious. I mostly use them to extract data from another layer in the same comp to use as a matte (alpha, luma, a color channel, or some other attribute). Sometimes, I use them for reflections, and every once in a blue moon, I will come up against a problem that only the Channel effects seem to be able to solve. So, even though their use is a little more abstract, ...