Specify a halftone screen frequency and resolution, About emulsion and image exposure – Adobe InDesign CC 2015 User Manual
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Printing
Last updated 6/6/2015
A 65 lpi: Coarse screen for printing newsletters and grocery coupons B 85 lpi: Average screen for printing newspapers C 133 lpi: High-quality
screen for printing four-color magazines
D 177 lpi: Very fine screen for printing annual reports and images in art books
The PPD files for high-resolution imagesetters offer a wide range of possible screen frequencies, paired with various
imagesetter resolutions. The PPD files for low-resolution printers typically have only a few choices for line screens,
usually coarser screens of between 53 lpi and 85 lpi. The coarser screens, however, give optimum results on
low-resolution printers. Using a finer screen of 100 lpi, for example, actually decreases the quality of your image when
you use a low-resolution printer for final output.
Specify a halftone screen frequency and resolution
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In the Output section of the Print dialog box, choose one of the following options:
• To select one of the preset screen frequencies and printer resolution combinations, choose an option in the
Screening menu.
• To specify a custom halftone screen frequency, select the plate to be customized, and then enter the lpi value in
the Frequency text box and a screen angle value in the Angle text box.
Note: Before creating your own halftone screens, check with your service provider for the preferred frequencies and angles.
Also, be aware that some output devices override the default frequencies and angles.
About emulsion and image exposure
Depending on the type of printing press used and how information is transferred from the film to the printing plates,
you may need to give your service provider film negatives or positives, with emulsion side up or down. Emulsion refers
to the photosensitive layer on a piece of film or paper. Typically, print service providers require negative film in the
United States and positive film in Europe and Japan. Check with your service provider to determine which emulsion
direction they prefer.
To tell whether you are looking at the emulsion side or the nonemulsion side (also referred to as the base), examine the
final film under a good light. One side appears shinier than the other. The dull side is the emulsion side; the shiny side
is the base.