Applying the Inner/Outer key

The following procedure provides a basic overview of how to apply this effect.

To apply the Inner/Outer key:

1. Select the border of the object that you want to extract by doing one of the following:
• Draw a single closed path near the object's border; then select the path from the Foreground menu and leave the Background menu set to None. Adjust the Single Mask Highlight Radius to control the size of the border around this path. (This method works well only on objects with simple edges.)
• Draw two closed paths: an inner path just inside the object, and outer path just outside the object. Make sure that any fuzzy or uncertain areas of the object lie within these two paths. Select the inner path from the Foreground menu and the outer path from the Background menu.

Note: Make sure that the mask mode for all paths is set to None.

2. If you want, move the masks around to find the location that provides the best results.
3. To extract more than one object, or to create a hole in an object, draw additional paths and then select them from the Additional Foreground and Additional Background menus. For example to key out a woman's hair blowing in the wind against a blue sky, draw the inner path inside her head, draw the outer path around the outside edge of her hair, and then draw an additional path around the gap in her hair where you can see sky. Select the additional path from the Additional Foreground menu to extract the gap and remove the background image.
4. Create additional open or closed paths to clean up other areas of the image, and then select them from the Cleanup Foreground or Cleanup Background menu. Cleanup Foreground paths increase the opacity along the path; Cleanup Background paths decrease the opacity along the path. Use the Brush Radius and Brush Pressure options to control the size and density of each stroke.

Note: You can select the Background (outer) mask as a Cleanup Background path to clean up noise from the background portions of the image.

5. Set Edge Thin to specify how much of the matte's border is affected by the key. A positive value moves the edge away from the transparent region, increasing the transparent area; Negative values move the edge toward the transparent region and increase the size of the foreground area.
6. Increase the Edge Feather values to soften edges of the keyed area. High Edge Feather values take longer to render.
7. Specify the Edge Threshold, which is a soft cutoff for removing low opacity pixels that can cause unwanted noise in the image background.
8. Select Invert Extraction to reverse the foreground and background regions.
9. Set Blend with Original to specify the amount you want the resulting extracted image to blend with the original image.