Adobe PHOTOSHOP 5.0, Руководство пользователя, Страница: 349 / 400

341 ADOBE PHOTOSHOP 5.0
User Guide
To modify the duotone curve for a given ink:
1
To preview any adjustments, select the Preview
option.
2
Click the curve box next to the ink color box.
The default duotone curve, a straight diagonal line
across the grid, indicates that you are mapping the
current grayscale value of every pixel to the same
percentage value of the printing ink. At this
setting, a 50% midtone pixel prints with a 50% dot
of the ink, a 100% shadow with a 100% dot of the
ink, and so on.
3
Adjust the duotone curve for each ink by
dragging a point on the graph or by entering
values for the different ink percentages.
The horizontal axis of the curve graph moves from
highlights (at the left) to shadows (at the right).
The density of the ink increases as you move up the
vertical axis. You can specify up to 13 points on the
curve. When you specify two values along the
curve, Adobe Photoshop calculates intermediate
values. As you adjust the curve, values are
automatically entered in the percentage text boxes.
The value you type in a text box indicates the
percentage of the ink color that will be used to
print that percentage of the image. For example, if
you enter 70 in the 100% text box, a 70% dot of
that ink color will be used to print the 100%
shadow areas of the image.
4 Click Save in the Duotone Curve dialog box to
save curves created with this dialog box.
5
Click Load to load these curves or curves
created in the Curves dialog box (including curves
created using the Arbitrary Map option). See
“Using the Curves command” on page 120 for
more information on adjusting curves, and
“Saving and loading duotone settings” on
page 342.
You can use the Info palette to display ink
percentages when you’re working with duotone
images. Set the readout mode to Actual Color to
see the ink percentages that will be applied when
the image is printed. These values reflect any
changes you’ve entered in the Duotone Curve
dialog box. (See “Using the Options palette” on
page 29.)
For a color illustration of duotone curves,
see figure 15-2 on page 228.
Specifying overprint colors
Overprint colors are two unscreened inks printed
on top of each other. For example, when a cyan ink
prints over a yellow ink, the resulting overprint is
a green color. The order in which inks are printed,
as well as variations in the inks and paper, can
significantly affect the final results.
To help you predict how colors will look when
printed, use a printed sample of the overprinted
inks to adjust your screen display. Just remember
that this adjustment affects only how the overprint
colors appear on-screen, not when printed. Before
adjusting these colors, make sure that you have
calibrated your system following the instructions
in Chapter 5, “Reproducing Color Accurately.”