Apple Shake 4 Tutorials - Manual (Page 198)

198 Chapter 6 Using Primatte
Under the right circumstances, this can reduce blue or green spill quite nicely. Under
the wrong circumstances, it can create a fuzzy halo around your edges—so use with
caution.
4 Set the replaceMode parameter back to “use image.”
You can also remove blue (or green) spill, before keying, by replacing it with a color
from your background. Other nodes that can remove spill suppression include Key–
SpillSuppress, Color–AdjustHSV, Filter–Blur, or Color–Monochrome applied to the
foreground image.
As you can see, there are many different ways to handle keying and spill suppression.
One popular trick is to place a Color–Monochrome node on the foreground image and
connect it as the replaceImage instead of the Blur node shown earlier.
The next set of steps show how to use a ColorReplace node to replace the blue spill on
the woman’s shirt with a color from the background image.
To use ColorReplace for spill suppression:
1 Insert a Color–ColorReplace node between the woman node and the Primatte1 node.
2 In the ColorReplace1 parameters, click to select the Source Color control, then drag over
the blue spill areas on the front edge of the woman’s shirt.
3 Click the Replace Color control again, then drag over a medium gray area of the
background.