Adobe PHOTOSHOP 5.0 User Manual page 250

242 CHAPTER 10
Using Channels and Masks
To edit a channel:
Use a painting or editing tool to paint in the image.
Paint with white to add to the channel; paint with
black to remove from the channel; paint with a
lower opacity or a color to add to the channel with
lower opacities.
Duplicating channels
You can duplicate any channel within or between
images. (You cannot duplicate a channel to a
Bitmap-mode image, however.) For example,
duplicate an image's channels to make a backup
before editing the channel. Or duplicate alpha
channels to a new image also to create a library of
selections that you can load into the current image
one by one—thus keeping the file smaller. If dupli-
cating between images, alpha channels must have
identical pixel dimensions (see "Creating new
images" on page 54).
To duplicate a channel using the Duplicate command:
1 In the Channels palette, select the channel to
duplicate.
Choose Duplicate Channel from the Channels
2
palette menu.
Type a name for the duplicate channel.
3
For Document, do one of the following:
4
Choose a destination. Only images with pixel
•
dimensions the same as the current image are
available. To duplicate the channel in the same file,
select the channel's current file.
Choose New to copy the channel to a new image,
•
creating a multichannel image containing a single
channel. Type a name for the new image.
5 To reverse the selected and masked areas in the
duplicate channel, select Invert.
6 Click OK.
To duplicate a channel by dragging:
In the Channels palette, select the channel you
1
want to duplicate.
Duplicate the channel:
2
To duplicate a channel within an image, drag the
•
channel into the image window or onto the New
Channel button ( ) at the bottom of the palette.
To duplicate the channel into another image,
•
make sure that the destination image is open.
Then drag the channel into the destination image
window.
Deleting channels
You may want to delete alpha channels you no
longer need before saving an image. Complex
alpha channels can substantially increase the disk
space required for an image.
To delete a channel with no confirmation:
1 Select the channel in the Channels palette.
2 Delete the channel:
Alt-click (Windows) or Option-click (Mac OS)
•
the Trash button.
Drag the channel name in the palette to the
•
Trash button.
Choose Delete Channel from the Channels
•
palette menu.