5.5

1055Motion User Guide
Refine Key tools
Use the Refine Key tools—Sample Color and Edges—to manually sample regions of an
image to modify the tolerance (core transparency) of the generated key.
• Sample Color: A button that activates an onscreen control to select regions of the
image to be turned transparent. Click the Sample Color tool, then drag a selection
rectangle in the canvas to define a range of color to key. After you create a selection
rectangle, you can resize it to sample more or fewer shades of color, increasing or
decreasing the range of background color used to create transparency. You can also
add more selection rectangles to expand the range of color that is keyed, or add more
selection rectangles at other frames of the clip to maintain transparency when lighting
conditions change. (To add selection boxes, select the Keyer filter in the Layers list,
then press and hold the Shift key while dragging in the canvas.)
Note: Adding a Sample Color selection box to a frame adds to the sampled region that’s
defined when you first apply this filter.
When you sample regions in multiple frames, keyframes are added to interpolate the
difference from one frame to the next. (Unlike standard keyframes, color-sampling
keyframes are hidden in the Motion window by default.) The Jump to Sample buttons let
you navigate between frames you’ve sampled, to make changes. For more information
on keyframing the Keyer filter, see Animating color key parameters in Motion.
• Edges: A button that activates an onscreen control to refine the transparency of
marginal regions of the keyed subject, such as hair, reflections, smoke, or moving
subjects with motion blur. Click the Edges tool, then drag in the canvas to draw a line
that crosses the boundary of the semitransparent region you want to adjust (with
one point on the keyed foreground subject and the other point on the transparent
background). Next, adjust the slider handle in the middle of this control line, outward to
soften the matte, or inward to harden it.