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Originally Posted by RichardGreaves |  | | | | | | | | | Many printers have Postscript ability, but usually that means they can translate Postscript output from graphic programs and out put them. This very often means the final output is 85 line halftones at 45 degrees and you can't adjust the options. Beware. | |  | |  | |
I'm not sure which printer you are talking about, but in the postscript language definition, any frequency and angle are allowed, but the actual value used will be the nearest mathematically allowable number.
In the print dialog box in a program such as illustrator, it may only show a single option for the LPI and angle. The number displayed in the print dialog box are controlled by a editable file know as a PPD. Printers create PPD's to describe the ideal numbers to be used for the printer to produce it's best possible output results. Since ideal for screen printing is different, the PPD could be edited to a default to other settings.
Within programs like illustrator, the values shown for LPI and angle can be edited in the file dialog box. While only 85lpi at 45 degrees is displayed, that value can be changed to 45 lpi at 15 degrees.
The exception i was referring to was high end color inkjet which is capable of near continuous tone. The postscript rip bundles with the printer can not produce a lined screen at all. Not at 85, not at 45, not at any number. Instead the rip is likely calculating stochastic screens using random diffusion dithering.
If a postscript printer can print any line screen, is should be able to print any line screen
fred