Game Development Reference
The Remove Color Matting Effect
The Remove Color Matting effect essentially does the same
thing that After Effects does when using the Premultiplied option
when interpreting an alpha channel. This is probably best done
in the Interpretation Settings dialog box in the Project panel.
Nevertheless, let's look at how color matting works, and how the
Remove Color Matting effect can remove it.
Open the Matting.aep project in the Chapter 5 folder of the
exercise fi les. This project contains a plant image that I rendered
from 3DS Max. When I created this fi le, I rendered it out using
a Premultiplied alpha channel, which means that there is some
residual background color in the alpha channel. Then, when I
imported this image into After Effects, I falsely labeled the alpha
interpretation as Straight. This left stray pixels around the edges
of the object. I'm now going to magnify this layer to 200%, so that
we can see them more clearly.
If you want to see this image without its alpha channel, you
can change the Show Channel and Color Management Settings
options at the bottom of the Composition panel to RGB Straight.
Hopefully, now, it will be easier to view the fringe blue pixels in
Figs. 5.47 and 5.48.
If you haven't done so already, switch the Show Channel and
Color Management Settings option to RGB, so that we can see our
alpha here. Apply the Remove Color Matting effect to this layer.
At fi rst, the results look bad because the default color it's trying to
Figure 5.47 The plant pre-
multiplied alpha comp in the