Using Masks; About Masks And Alpha Channels - Adobe PHOTOSHOP CS2 User Manual

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
•
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
•
cumulative effect. If there is no clear edge, the Edge Touchup tool adds opacity to the object or subtracts opacity
from the background.
You can also clean up the image after an extraction by using the Background Eraser and History Brush tools in the
toolbox.
Click OK to apply the final extraction. On the layer, all pixels outside the extracted object are erased to trans­
8
parency.

Using masks

About masks and alpha channels

When you select part of an image, the area that is not selected is "masked" or protected from editing. So, when you
create a mask, you isolate and protect areas of an image as you apply color changes, filters, or other effects to the rest
of the image. You can also use masks for complex image editing such as gradually applying color or filter effects to
an image.
A B
Examples of masks
A. Opaque mask used to protect the background and edit the butterfly B. Opaque mask used to protect the butterfly and color the
background C. Semitransparent mask used to color the background and part of the butterfly
In Photoshop, masks are stored in alpha channels. Masks and channels are grayscale images, so you can edit them
like any other image. With masks and channels, areas painted black are protected, and areas painted white are
editable.
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ADOBE PHOTOSHOP CS2
. The tool subtracts opacity and has a
. The tool sharpens edges and has a
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