Datasheet

643
Book IX
Chapter 1
Prepping Graphics
for Print
Getting the Right Resolution, Mode, and Format
Screen frequencies
For the recommended resolution for color separations in Table 1-1, I list 2
multiplied by the number of lines per inch. The lines per inch, or lpi, per-
tains to the screen frequency of the output device. Screen frequencies are
measured in lines per inch in a halftone screen. You may also hear the terms
screen ruling or line screen. When images are printed, they’re converted into
a series of dots called halftones. When you print your halftone, you print it
by using a halftone screen of a certain value. The average screen frequency
for printing four-color images is 133 to 175 lpi. Therefore, when you multiply
that number by 2, you need to create your images by using a resolution set-
ting of 266 to 350 dots per inch (dpi).
File formats
As far as file formats go, what you choose depends on a couple of issues:
✓ What you intend to do with the image — print it to a laser printer, order
prints from an online photo printer?
✓ What does your service bureau, offset printer, client, director, or
another interested party prefer?
Table 1-2 lists some of the more popular recommended formats for specific
jobs, but again, communicate with the parties involved to see what’s ulti-
mately the best format to use.
Table 1-2 Recommended File Formats
Job Formats
Color inkjet printouts EPS, TIFF, PDF, PSD
Color separations PSD, PDF, EPS, TIFF, DCS 2.0
Spot color separations PSD, PDF, DCS 2.0 if importing into another
application
Magazines/brochures EPS, TIFF, PDF
Newspapers TIFF, PDF
Importing to page layout programs TIFF, EPS, PSD, PDF
Importing to illustration programs EPS, TIFF, DCS, PSD, PDF
Slides TIFF, PowerPoint, PICT, PCX, EPS
(some bureaus can’t do EPS)
Photo prints JPEG, TIFF
Word documents TIFF, EPS
E-mailing for workflow review PDF