Apple Shake 4 - Manual (Page 618)

618 Chapter 23 Color Correction
In the following example, an artifact of Internet pop culture is recreated using a Text
node. The default black background color is raised to blue with an Add node.
When the image is panned, blue continues to appear in the area that was previously
outside of the frame.
To create a black outline, insert a Crop node before the Pan in the node tree: