Adobe PHOTOSHOP 6.0 Manual page 210

CHAPTER 7
200
Using Channels and Masks
Creating alpha channels (Photoshop)
You can create a new alpha channel and then use
painting or editing tools to add the mask to it.
To create an alpha channel using current options:
1 Click the New Channel button ( ) at the
bottom of the Channels palette. The new channel
is named according to the sequence in which it
was created.
Use a painting or editing tool to paint in the
2
image. Paint with black to add to the channel;
paint with white to remove from the channel;
paint with a lower opacity or a color to add to the
channel with lower opacities.
To create an alpha channel and specify options:
Do one of the following:
1
Alt-click (Windows) or Option-click (Mac OS)
•
the New Channel button ( ) at the bottom of
the palette.
Choose New Channel from the Channels
•
palette menu.
Type a name for the channel.
2
3 Select display options for the channel, as
described in steps 2 through 4 of the procedure for
changing Quick Mask options in "Creating
temporary masks in Quick Mask mode
(Photoshop)" on page 197. Alpha channel options
are identical to Quick Mask options.
Click OK. A new channel appears at the bottom
4
of the Channels palette and is the only channel
visible in the image window.
5 Click the eye icon ( ) next to a color channel or
the composite color channel to display the image
with a color overlay.
6 Use a painting or editing tool to paint in the
image. Paint with black to add to the new channel,
paint with white to remove from the new channel,
or paint with a lower opacity or a color to add to
the new channel with lower opacities.
Saving a mask selection
You can save any selection as a mask in a new or
existing alpha channel.
To save a selection to a new channel with default
options (Photoshop):
Select the area or areas of the image that you
1
want to isolate.
Click the Save Selection button ( ) at the
2
bottom of the Channels palette. A new channel
appears, named according to the sequence in
which it was created.
To save a selection to a new or existing channel:
Select the area or areas of the image that you
1
want to isolate.
Choose Select > Save Selection.
2
In the Save Selection dialog box, choose a
3
destination image for the selection in the
Document menu.
By default, the selection is placed in a channel in
your active image. You can choose to save the
selection to a channel in another open image with
the same pixel dimensions or to a new image.