User Guide

Chapter 5: Painting And Image Editing
Saving and loading selections in channels
When you have made a selection in an image, you can create an alpha channel from the selection. An
alpha channel preserves the shape and opacity of a selection, so you can use it to make the same
selection in the image again.
You can think of an alpha channel as a mask that selects some areas and protects other areas from
painting and image editing. Because alpha channels make precise selections of varying intensities,
alpha channels let you control which areas in an image will be affected by painting tools and filters,
and the intensity of the effects.
When you view an alpha channel, you see a grayscale image. When the channel is made from a
selection, it contains white areas representing fully selected pixels, black areas representing
unselected pixels, and gray areas representing pixels that are partially selected, with the gray
lightness values corresponding to the selection opacity.
This section describes how to save a selection in a channel, and how to load a channel to make a
selection in an image, using dialog boxes. You can also use shortcuts in the Channels palette, as
described under "Channels palette options" on page 504.
To save a selection in a channel:
1. With an active selection in an image, choose Image | Select | Save.
2. In the Operation area of the Save Selection dialog box, select New Channel and click OK.
You can also click the Selection button in the Channels palette to save the current selection in a new
channel.
To load a selection from a channel:
1. With a paint object in edit mode, choose Image | Select | Load.
2. In the Load Selection dialog box, choose a channel name in the Channel pop-up menu. To
invert the selection, click Invert.
3. Choose an option in the Operation area and click OK.
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