Apple Motion 5.1.1 - Manual (Page 497)

Chapter 13 Keying 497
•
Lighten: Compares overlapping pixels from the foreground and background layers, then
preserves the lighter of the two. Good for creating a selective light wrap effect.
•
Screen: Superimposes lighter portions of the background layer over wrapped areas of the
keyed foreground layer. Good for creating an aggressive light wrap effect.
•
Overlay: Combines the background layer with the wrapped areas of the keyed foreground
layer so overlapping dark portions become darker, light portions become lighter, and colors
become intensified.
•
Hard Light: Similar to the Overlay composite mode, except that colors become muted.
Mix slider
Use this slider to set the percentage of the original image to be blended with the keyed image.
100% is the fully keyed image, while 0% is the original, unkeyed image.
Use the Keyer filter
Getting started with the Keyer filter is easy. After you create a basic key, you can fine-tune
the default color sampling using the Sample Color and Edges tools in the Filters Inspector
or HUD. Alternatively, you can override the Keyer filter’s default sampling, then set the key
colors manually.
When manually sampling colors to create a key, it’s not necessary to click the Sample Color
and Edges tools in the Inspector or HUD before you drag in the Canvas. Instead, you can use
keyboard shortcuts to activate the Sample Color and Edges tools while dragging in the Canvas.
For additional control over the transparency matte, use the Color Selection controls and the
Matte Tools in the Filters Inspector. These controls provide options for creating a seamless
composite without adding more Keyer filters.
Create a basic key
1 Import a background image into your project.
2 Import a foreground image or video clip of a subject positioned in front of a green screen or
blue screen.
This example uses video footage of an actor standing in front of a green screen. Make sure the
foreground (the actor and green screen) layer is above the background layer in the Layers list.
3 Move the playhead to a frame where the green screen is visible in the Canvas, then apply the
Keyer filter to the foreground layer.
The Keyer filter analyzes the frame and guesses the color you are trying to remove, based on the
dominant color in the image (if blue or green). For the best results, apply the filter to the frame
with the greatest amount of the color to key.
If the automatic guess is incorrect (for example, if you want to key on red), you can set the
Strength parameter in the Filters Inspector to 0 to disable automatic color sampling, then use the
Sample Color tool to draw a selection box in the Canvas around the color you want to key. (This
workflow is covered in the next task.)
67% resize factor