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发信人: killest (矛盾), 信区: Graphics
标  题: PHOTOSHOP(109)-Printing
发信站: 紫丁香 (Sun May 10 17:44:12 1998), 转信

Printing registration marks
The Registration Marks option in the Page Setup
dialog box prints registration marks on the image,
including bull抯-eyes and star targets. These marks
are used primarily for aligning color separations
and duotones.
Printing a negative
The Negative option in the Page Setup dialog box
prints an inverted version of the image. Unlike the
Invert command in the Image menu, the Negative
option converts only the output to a negative (not
the on-screen image). If you are printing separa-tions
directly to film, you will probably want a
negative, although in many countries, it is com-mon
to print film positives. Check with your print
shop to determine if it requires a film positive or
negative. If you are printing to paper, print a
positive.
Specifying an emulsion side
Emulsion refers to the photosensitive layer on a
piece of film or photographic paper. By default, the
emulsion is up (right reading); type in the image is
readable when the photosensitive layer is facing
you. When you select the Emulsion Down option
(also right reading), type is readable when the
photosensitive layer is facing away from you. Nor-mally,
images printed on paper should be printed
emulsion up.
To determine the emulsion side of a piece of film,
examine the film under a bright light after it has
been developed. The dull side is the emulsion; the
shiny side is the base. Check with your print shop
to see whether it requires film with positive emul-sion
up, negative emulsion up, positive emulsion
down, or negative emulsion down.
Using interpolation
Some PostScript Level 2 printers can reduce the
jagged appearance of a low-resolution image by
automatically resampling up an image while it is
printing. If your printer does not have this capabil-ity,
this option has no effect.
Printing a border
You can specify the width of a border you want to
have appear around an image by using the Border
button. The border is printed in black.
To specify the width of a border:
1 Click Border in the Page Setup dialog box.
2 For Width, enter a value for the width of the
border; then choose a unit of measurement and
click OK. You can specify decimal values for the
width.
Printing a caption
Select the Caption option in the Page Setup dialog
box when you want to print the text you entered
for the caption in the File Info dialog box. See
揂dding file information� on page 307. Caption
text is printed as 9-point Helvetica plain. This font
cannot be changed.
333
Selecting a background color
The Background button in the Page Setup dialog
box lets you select a background color to be
printed on the page outside the image area. This
option is especially useful if you are printing slides
to a film recorder, because a black or colored back-ground
is often desirable for slides. To use this
option, click Background; then select a color from
the Color Picker dialog box. The Background
option is a printing option only and does not affect
the image area itself.
Creating bleed
The Bleed button lets you print crop marks inside
the image instead of outside the image. Use this
when you want to trim the image within the
graphic. You can specify the width of the bleed.
Displaying the transfer functions
The Transfer button in the Page Setup dialog
box lets you adjust the transfer functions that
Adobe Photoshop uses to print the image. Transfer
functions are traditionally used to compensate for
dot gain or dot loss that may occur when an image
is transferred to film. For information on setting
the transfer functions, see 揅ompensating for dot
gain using transfer functions� on page 92.
Selecting halftone screen
attributes
Halftone screen attributes include the screen fre-quency
and dot shape for each screen used in the
printing process. For color separations, you must
also specify an angle for each of the color screens.
Setting the screens at different angles ensures that
the dots placed by the four screens blend to look
like continuous color and do not produce moir�
patterns.
Check with your print shop for the preferred fre-quency,
angle, and dot settings before creating
your halftone screens. (In general, the default
angle settings should be used unless your printer
specifies that they be changed.)
To define the screen attributes:
1 Click Screen in the Page Setup dialog box. The
following illustration shows the Halftone Screens
dialog box as it appears for a CMYK image.
2 Deselect Use Printer抯 Default Screens, and set
the screen frequency and angle for each screen.
The screen frequencies and angles for grayscale
and color halftones are discussed in the sections
following this procedure.
Note: To use the default halftone screen built into the
printer, select Use Printer抯 Default Screens. The
specifications from the Halftone Screens dialog box
are then ignored when the halftone screens are gener-ated.
3 For Shape, choose the dot shape you want. If
you want all four screens to have the same dot
shape, select Use Same Shape For All Inks.
Choosing Custom from the Shape menu displays
the Custom Spot Function dialog box, which lets
you define your own dot shapes by entering
PostScript commands. The Custom Spot Function
is useful for printing with nonstandard halftone
algorithms. For information about using
PostScript language commands, see the PostScript
CHAPTER 14 334
Printing
Language Reference Manual published by Addi-son-
Wesley, or consult the imagesetter抯 manufac-turer.
For optimal printing, the image resolution should
be twice the halftone screen frequency. If the reso-lution
is more than 2.5 times the screen frequency,
Adobe Photoshop displays an alert message. See
揑mage resolution and screen frequency� on
page 40 for more information.
Selecting screen attributes for a
grayscale halftone
For a grayscale image, enter a screen frequency
from 1 to 999.999 for Frequency; then choose the
unit of measurement you want.
For Angle, enter a screen angle from �180 to +180
degrees.
Selecting screen attributes for a color
separation
To print halftones for a color separation, choose
the color of the screen for Ink, and manually enter
the frequency and angle for each of the four
screens; or you can choose to have Adobe
Photoshop enter the frequency and angles for each
screen. To do this, click the Auto button, and in the
Auto Screens dialog box, enter the resolution of
the output device and the screen frequency you
intend to use. When you click OK in the Auto
Screens dialog box, Adobe Photoshop determines
the best frequencies and angles for the four half-tone
screens and enters these values in the Half-tone
Screens dialog box. Changing these values
may result in moir� patterns.
If you are using a high-resolution output device
equipped with PostScript Level 2 or an Emerald
controller, make sure that the Use Accurate
Screens option is selected in the Auto Screens dia-log
box (or in the Halftone Screens dialog box if
you抮e entering the values manually). The Use
Accurate Screen option lets the program access the
correct angles and halftone screen frequencies for
high-resolution output. If your output device is
not equipped with PostScript Level 2 or an Emer-ald
controller, this option has no effect.
Saving and loading halftone screen
settings
You can save your halftone screen settings for
use with other Adobe Photoshop files by clicking
the Save and Load buttons in the Halftone Screens
dialog box. To save the new settings as the default,
hold down Option (Macintosh) or Alt (Windows),
and click the �> Default button. To return to the
original default settings, hold down Option/Alt
and click <桪efault.
Additional printing options
You can also set printing options by using the Print
dialog box, which appears when you choose File >
Print. These options let you print only a selected
area of an image, transfer image data to the output
device in ASCII format, and print a color-cor-

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