Offset Printing - Xerox DocuColor 40 Reference Manual

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1-14 Desktop Color Primer

Offset printing

For jobs that will be proofed on the DocuColor 40 CP in preparation for being
printed on an offset press:
• Work in the CMYK color model only (see the application notes). All elements in
your document, including placed images, must be in the CMYK color model to
create film separations for printing.
• When choosing or defining colors in your application, use the DocuColor 40 CP
color reference pages to be assured of predictable results (see Chapter 3).
• If cost is a factor and the document does not contain CMYK images, consider using
two or three PANTONE colors, instead of the standard four process colors (see
Chapter 3). This reduces the number of film separations and printing plates needed
to print the job.
• If your document contains high-resolution CMYK raster images, you can reduce
processing time by saving the images in Encapsulated PostScript (EPS) format with
Photoshop using Desktop Color Separations (DCS). A DCS image consists of five
separate files—one for each of the CMYK color channels of the image, plus one low-
resolution master composite file that you use for placement in the document (see
your Photoshop documentation). The low-resolution master file provides a
composite preview of the image for screen viewing and is used to print composites.
DCS files do not use less disk space than single CMYK files, but they do reduce the
amount of time needed to send image data to the printer. DCS files can be used to
create film separations as well.
• Use the Combine Separations print option to check for trapping problems (see the
Printing Guide).
• Choose the appropriate CMYK Simulation and CMYK Simulation Method settings
(see Chapter 2).