Adobe Photoshop CS4 - Manual (Page 658)

651 USING PHOTOSHOP CS4
Optional plug-ins
Last updated 1/10/2010
Smooth Enter a value or drag the slider to increase or decrease the smoothness of the outline. It’s usually best to begin
with zero or a small value to avoid unwanted blurring of details. If there are sharp artifacts in the extraction result, you
can increase the Smooth value to help remove them in the next extraction.
Channel Choose the alpha channel from the Channel menu to base the highlight on a selection saved in an alpha
channel. The alpha channel should be based on a selection from the edge boundary. If you modify a highlight based
on a channel, the channel name in the menu changes to Custom. Your image must have an alpha channel for the
Channel option to be available.
Force Foreground Select this option if the object is especially intricate or lacks a clear interior.
3 Select the Edge Highlighter tool , and draw to define the edge of the object you want to extract. Drag so that the
highlight slightly overlaps both the foreground object and its background. Use a large brush to cover wispy,
intricate edges where the foreground blends into the background, as with hair or trees.
Use either the Zoom tool or the Hand tool to adjust the view as needed.
If you need to erase the highlight, select the Eraser tool , and drag it over the highlight. To erase the entire
highlight, press Alt+Backspace (Windows) or Option+Delete (Mac OS).
If the object has a well-defined interior, make sure the highlight forms a complete enclosure. You do not need to
highlight areas where the object touches the image boundaries. If the object lacks a clear interior, highlight the entire
object.
Note: You can’t highlight the entire object if you’ve selected Textured Image or Force Foreground.
4 Define the foreground area by doing one of the following:
• If the object has a well-defined interior, select the Fill tool . Click inside the object to fill its interior. Clicking a
filled area again with the Fill tool removes the fill.
• If you’ve selected Force Foreground, select the Eyedropper tool , and click inside the object to sample the
foreground color, or click in the Color text box and use a Color Picker to select the foreground color. This technique
works best with objects that contain tones of a single color.
5 (Optional) Click Preview to preview the extracted object. Zoom in as needed.
Show Choose a menu option to switch between views of the original and the extracted image.
Display Choose a menu option to preview the extracted object against a colored matte background or a grayscale
background. To display a transparent background, choose None.
6 (Optional) Improve the extraction by doing one of the following:
• Choose new Highlight and Fill options and draw again with the Edge Highlighter tool. Define the foreground area
once more, and then preview the extracted object.
• Specify new Extraction settings (Smooth, Force Foreground, or Color) and then preview the extracted object.
When you are satisfied with the extraction, you can do the final touchups.
7 Touch up the extraction results by doing one of the following:
• To erase background traces in the extracted area, use the Cleanup tool . The tool subtracts opacity and has a
cumulative effect. You can also use the Cleanup tool to fill gaps in the extracted object. Hold down Alt (Windows)
or Option (Mac
OS) while dragging to add back opacity.
• To edit the edge of the extracted object, use the Edge Touchup tool . The tool sharpens edges and has a
cumulative effect. If there is no clear edge, the Edge Touchup tool adds opacity to the object or subtracts opacity
from the background.