User's Manual

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ADOBE PHOTOSHOP CS2
User Guide
Note: When the new channel appears at the bottom of the Channels palette, it is the only channel visible in the image
window unless you click a color channel or the composite color channel.
7 Select a painting or editing tool and do one of the following to add or subtract from the mask created from the
alpha channel:
• To remove areas in the new channel, paint with white.
• To add areas in the new channel, paint with black.
• Add or remove areas using opacities less than 100%, set the opacity in the options bar of the painting or editing
tool and then paint with white or black. You can also paint with a color to achieve lower opacities.
See also
“About masks and alpha channels” on page 338
Properties of alpha channels
An alpha channel has these properties:
• Each image can contain up to 56 channels, including all color and alpha channels.
• You can specify a name, color, mask option, and opacity for each channel. (The opacity affects the preview of the
channel, not the image.)
• All new channels have the same dimensions and number of pixels as the original image.
• You can edit the mask in an alpha channel using painting tools, editing tools, and filters.
Original mask (left), and after a filter was applied (right)
• You can convert alpha channels to spot color channels.
To save a mask selection
You can save any selection as a mask in a new or existing alpha channel.
1 Select the area or areas of the image that you want to isolate.
2 Click the Save Selection button at the bottom of the Channels palette. A new channel appears, named
according to the sequence in which it was created.