Quick links to procedures on this page:

Saving selections as alpha channels

You can create alpha channels to store multiple selections in a document. An alpha channel is a temporary storage area for both path-based and pixel-based selections. To reuse a selection in other documents, you can store the selection in the Selection Portfolio. It is important to note that the Selection Portfolio stores only path-based selections. For more information see, Working with the Selection Portfolio.

You can create an alpha channel from the current selection to copy its editable and protected areas. You can also combine a new selection with one that was previously stored in an alpha channel. To reactivate a selection that was previously saved as an alpha channel, simply load it in the image. Loading a selection reactivates it on the canvas, where it controls painting and image effects.

Combining selections when saving or loading alpha channels

When you save or load alpha channels, you can combine the current selection with an existing alpha channel by adding, subtracting, or intersecting with the selection. Adding to a selection combines it with the existing channel. Subtracting a selection cuts it out of the existing channel. When intersecting a selection, you include only those parts that are common to the selection and the existing channel.

In the following set of owl images, the artist created and saved selections for each area that she wanted to work with separately — the eyes, the beak, and the outline. To show the selections clearly in these images, the selections were saved to channels, reloaded, and displayed as red overlays. For more information, see To view or hide a channel.

The following images show the step-by-step creation of a precise "face" selection that excludes the beak and eyes. The purpose of the precise selection of the face is to control the brushstrokes and constrain effects.

 

A "face" selection is drawn roughly by using the Lasso tool. The eyes, the beak, and a portion of the background are included.
To save a selection to a new alpha channel Back to Top

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Alpha channels are pixel based, therefore, any path-based selections are saved as pixel-based selections.

If you do not specify a name, the new channel is named incrementally with the previous channel: Alpha 1, Alpha 2, and so on.

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You can also save a selection to a channel by clicking the Save Selection As Channel button in the Channels panel.

To combine a selection with an existing alpha channel Back to Top

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You can also save a selection to a channel by clicking the Save Selection As Channel button in the Channels panel.

To load a selection from an alpha channel Back to Top

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You can also load a selection from an alpha channel by clicking the Load Channel As Selection button in the Channels panel.


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