Game Development Reference
In-Depth Information
5
THE CHANNEL EFFECTS
The Channel effects category are diffi cult to defi ne. 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 fi lled with both advanced- and obsolete effects,
and their practical usage is not always obvious. I use them mostly
for refl ections, but every once in a while, I 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, it still pays to
be familiar with these tools. As a prerequisite to understanding
this chapter, I strongly recommend acquiring intimate familiarity
with channels, color relationships, and blend modes.
The Alpha Levels Effect
The Alpha Levels effect is like the Powerful Levels effect (that
will be discussed in the next chapter), but it only operates on the
alpha channel of a layer. You can use it to make semi-transparent
areas completely opaque or completely transparent, or to make
transparent areas opaque and vice versa.
To see this effect in action, open the Alpha Levels.aep project
from the Chapter 5 folder of the exercise fi les. This project con-
tains art by the Yo Gabba Gabba artist, Will Kindrick (Fig. 5.1).
In the Dragon Fire FINAL comp, apply the Alpha Levels effect
to the Precomposed Layers comp. Nothing happens by default.
Further, before we change these settings, let's look directly at the
alpha channel of our layer. At the bottom of the Composition
panel, click the three interlaced circles (the Show Channels and
Color Management Settings button) to view the different chan-
nels used to create this result. Change the channel to Alpha to
view the alpha channel. The black areas represent transparent
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