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 repre-
senting fully selected pixels, black areas representing unselected pix-
els, 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 33.671.
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.
Option
Result
New Selection
Removes any current selections and cre-
ates a new selection