5.5

856Motion User Guide
• Replace: Completely replaces the image object’s alpha channel as well as any other
masks that appear beneath the mask in the Layers list. In the following example, the
circle mask overrides the rectangle mask, because the circle mask (set to Replace)
appears above the rectangle mask in the Layers list. See Combining multiple masks
in Motion.
• Intersect: Shows pixels only in regions where masks overlap. In the following
example, only the overlapping areas of the rectangle and circle masks are visible.
In another example, if you import a TIFF file with an alpha channel and you want to
cut out part of it without losing alpha information, you must use the Intersect blend
mode. This is also true for layers with keying filters applied.
• Invert Mask: A checkbox that, when selected, reverses the mask—swapping its solid and
transparent areas. This is useful if you need to switch the solid and transparent areas of
an existing mask.