Blending modes for layers control how each
layer blends with or interacts with layers beneath it. Blending
modes for layers in After Effects (formerly referred to as layer
modes and sometimes called transfer modes) are
identical to blending modes in Adobe Photoshop.
Most blending
modes modify only color values of the source layer, not the alpha channel.
The Alpha Add blending mode affects the alpha channel of the source layer,
and the silhouette and stencil blending modes affect the alpha channels
of layers beneath them.
You can’t directly animate blending
modes by using keyframes. To change a blending mode at a certain
time, split the layer at that time and apply the new blending mode
to the part of the layer that continues. You can also use the Compound
Arithmetic effect, the results of which are similar to the results
of blending modes but can change over time.
Each layer has
a blending mode, even if that blending mode is the default Normal blending
mode.
Note: To blend colors with a gamma value of 1, choose
File > Project Settings and select Blend Colors Using
1.0 Gamma. Deselect this option to blend colors in the working color
space for the project. (See
Linearize working space and enable linear blending.)
Blending
modes for multiple masks on a single layer are called mask
modes.
Some effects include their own blending mode
options. For details, see the descriptions of the individual effects.
Trish and Chris Meyer provide tips and tricks for using
blending modes to achieve a filmic look in this PDF document on
the Artbeats website.
Trish and
Chris Meyer explain how to use blending modes, layer styles, and
the Displacement Map effect to make text blend in to appear to be
part of a surface in the PDF article “Writing on the Wall” on the Artbeats
website.