Adobe PHOTOSHOP 5.0 User Manual page 252

244 CHAPTER 10
Using Channels and Masks
Splitting channels into separate images
Choosing the Split Channels command from the
Channels palette menu splits the various channels
in an image into separate images. The original file
is closed and individual channels appear in
separate grayscale image windows. The title bar
shows the original name plus the channel abbrevi-
ation (Windows) or full name (Mac OS). Any
changes since the last save are retained in the new
images, lost in the original.
Splitting channels is useful when you want to
retain the individual channel information in a file
format that doesn't preserve channels.
Note: Only flattened images can be split (see
"Flattening all layers" on page 269).
Merging channels
Multiple grayscale images can be combined into a
single image. Some grayscale scanners let you scan
a color image through a red filter, a green filter, and
a blue filter to generate red, green, and blue
images. Merging lets you combine the separate
scans into a single, color image.
Note: You can also blend the data in one or more
channels into an existing or new channel (see
"Mixing channels" on page 243).
Images must be in Grayscale mode, have the same
pixel dimensions, and be open. (See "Changing
the pixel dimensions of an image" on page 49.)
The number of grayscale images you have open
determines the color modes available when
merging channels. For example, you can't merge
the split channels from an RGB image into a
CMYK image, because CMYK requires four
channels and RGB only three.
Note: If you are working with DCS files that have
accidentally lost their links (and so cannot be
opened, placed, or printed), open the channel files,
and merge them into a CMYK image. Then resave
the file as a DCS EPS file.
To merge channels:
1 Open the grayscale images containing the
channels you want to merge.
2 Make one of the images active.
Choose Merge Channels from the Channels
3
palette menu.
For Mode, choose the color mode you want to
4
create. If an image mode is unavailable, it is
dimmed. The number of channels appropriate for
the mode appears in the Channels text box.
5 If necessary, enter a number in the Channels
text box.
If the number is incompatible with the selected
mode, Multichannel mode is automatically
selected. This creates a a multichannel image with
two or more channels.