Adobe PHOTOSHOP 6.0 Manual page 398

CHAPTER 14
388
Printing (Photoshop)
The image is converted to a multichannel image,
with each channel represented as a spot-color
channel. The contents of each spot channel
accurately reflect the duotone settings, but the
on-screen composite preview may not be as
accurate as the preview in Duotone mode.
Important: If you make any changes to the image in
Multichannel mode, you will be unable to revert to
the original duotone state (unless you can access the
duotone state in the History palette). To adjust the
distribution of ink and view its effect on the
individual printing plates, make the adjustments in
the Duotone Curves dialog box before converting to
Multichannel mode.
Select the channel you want to examine in the
2
Channels palette.
Choose Edit > Undo Multichannel to revert to
3
Duotone mode.
Printing duotones
When creating duotones, keep in mind that both
the order in which the inks are printed and the
screen angles you use dramatically affect the
final output.
Click the Auto button in the Halftone Screens
dialog box to set the optimal screen angles and
frequencies. (See "Selecting halftone screen
attributes" on page 379.) Make sure that you select
Use Accurate Screens in the Auto Screens dialog
box if you're printing to a PostScript Level 2
(or higher) printer or an imagesetter equipped
with an Emerald controller.
Note: The recommended screen angles and
frequencies for quadtones are based on the
assumption that channel 1 is the darkest ink and
channel 4 is the lightest ink.
You do not have to convert duotone images to
CMYK to print separations—simply choose
Separations from the Profile pop-up menu in the
Color Management section of the Print Options
dialog box. (See "Printing color separations" on
page 389.) Converting to CMYK mode converts
any custom colors to their CMYK equivalents.
Exporting duotone images to other
applications
To prepare a duotone image for exporting to a
page-layout application, save the image in EPS or
PDF format (unless the image contains spot
channels, in which case you should convert it to
Multichannel mode and save it in DCS 2.0
format). Keep in mind that it's important to name
custom colors so they'll be recognized by the other
application. Otherwise the image won't print
correctly—or might not print at all.