Apple Motion 5.1.1 - Manual (Page 492)

Chapter 13 Keying 492
These controls are meant to be used after you begin creating a key using automatic sampling
or the Sample Color and Edges tools. (However, you can skip those tools and create a key using
the Color Selection controls in Manual mode.) The graphical Chroma and Luma controls in the
Color Selection group provide a detailed way of refining the range of hue, saturation, and image
lightness that define the keyed matte.
Before you adjust these controls, the graphs in the Chroma and Luma controls represent ranges
of color and luma in the image that have been automatically and manually sampled (using the
Refine Key tools and the Strength slider).
The Color Selection group contains the following controls:
•
Graph: Select one of two buttons to set how the adjustable graphs in the Chroma and Luma
controls are used to fine-tune a key:
•
Scrub Boxes: Select this button to limit the Chroma and Luma controls to adjusting softness
(edge transparency) in the matte you are creating. In Scrub Boxes mode, you cannot
manually adjust tolerance (core transparency), which is determined by the Keyer filter’s
automatic sampling, plus any Sample Color selection boxes you’ve added in the Canvas. To
increase matte tolerance, add more Sample Color selection boxes or adjust the Strength
slider.)
•
Manual: Select this button to use the Chroma and Luma controls to adjust the softness
(edge transparency) and tolerance (core transparency) in the matte you are creating. Make
sure the Strength slider is set to a value greater then 0 before you switch into Manual mode,
otherwise the Chroma and Luma controls are disabled. When you switch to Manual mode,
the Refine Key tools and Strength slider become disabled, but samples you’ve made with
those controls continue to contribute to the matte.
Important: When you switch to Manual mode, it’s inadvisable to switch back to Scrub Boxes
mode. For best results, begin keying an image using the Sample Color and Edges tools in
Scrub Boxes mode. Switch to Manual mode afterwards if you feel it’s necessary to refine
your matte using the Chroma and Luma controls. However, after you switch to Manual
mode, do not switch back to Scrub Boxes mode. If you do, you may experience unexpected
combinations of additionally sampled and keyframed values that might be difficult to control.
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