Game Development Reference
The Compound Arithmetic Effect
The Compound Arithmetic effect is exactly like a watered down
version of the Calculations effect. It allows you to combine differ-
ent attributes from two different layers (Fig. 5.33).
Figure 5.33 The options in the
Compound Arithmetic effect
follow the same basic structure
as the Calculations effect does.
Use the Second Source Layer drop down to select a second
layer to blend with the current layer. Choose a blend operation
with the Operator drop down, and a few other self-explanatory
properties. For more control, use the Calculations effect.
The Invert Effect
In Photoshop, there is an Invert adjustment. For this adjust-
ment, there are no options available. You simply apply it, it inverts
the colors of your layer and you're done. Boom. End of story. The
Invert effect in the After Effects is much more exciting because it
allows you to invert all kinds of stuff, not just the composite col-
ors. However, if a simple inversion is what you're looking for, then
just apply it and walk away.
To obtain this look at the Invert effect, open up the Invert.aep
project in the Chapter 5 folder of the exercise fi les. This project
contains a logo I created in Adobe Illustrator (Fig. 5.34).
Apply the Invert effect to this, and instantly the colors of
the logo are inverted. If you've been looking for the standard
Photoshop Invert adjustment, there you go (Fig. 5.35).
The great thing about this effect is that taking it to the next
level is very simple. Other than the ubiquitous Blend With
Original setting (basically the opacity of the effect), there is only
one setting here—Channel. In the Channel drop down, you spec-
ify which attribute of the current layer is inverted. And, that's all
there is to it.
Let's take the green channel, for instance. Change the Channel
value to Green. This inverts the green channel, and the green
channel only. Because there is no green light used to make
black, all black areas become 100% green. So, the red and blue