Storing Masks In Alpha Channels - Adobe PHOTOSHOP 6.0 Manual

• Selected Areas to have masked or protected areas
appear white (transparent) and to have selected
areas appear black (opaque). Painting with white
increases the masked, protected area; painting
with black increases the selected area.
With this option, the Quick Mask button in the
toolbox appears as a gray circle on a white
background ( ).
To toggle between the Masked Areas and
Selected Areas options for quick masks, Alt-click
(Windows) or Option-click (Mac OS) the Quick
Mask mode button.
To choose a new mask color, click the color box,
3
and choose a new color.
For more information, see "Using the
Adobe Color Picker" in online Help.
4 To change the opacity, enter a value between 0%
and 100%.
Both the color and opacity settings affect only the
appearance of the mask and have no effect on how
underlying areas are protected. Changing these
settings may make the mask more easily visible
against the colors in the image.
Click OK.
5
You can convert this temporary mask to a
permanent alpha channel by switching to standard
mode and choosing Select > Save Selection.

Storing masks in alpha channels

In addition to the temporary masks of Quick Mask
mode, you can create more permanent masks by
storing them in alpha channels. This allows you to
use the masks again in the same image or in a
different image.
You can create an alpha channel in Photoshop and
then add a mask to it. You can also save an existing
selection in a Photoshop or ImageReady image as
an alpha channel that will appear in the Channels
palette in Photoshop.
About alpha channels (Photoshop)
An alpha channel has these properties:
Each image (except 16-bit images) can contain
•
up to 24 channels, including all color and alpha
channels.
All channels are 8-bit grayscale images, capable
•
of displaying 256 levels of gray.
You can specify a name, color, mask option,
•
and opacity for each channel. (The opacity affects
the preview of the channel, not the image.)
All new channels have the same dimensions and
•
number of pixels as the original image.
• You can edit the mask in an alpha channel using
the painting and editing tools.
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User Guide