What is Postscript
Postscript is an interpreted computer programming language designed to describe graphics rich pages for print.
When your computer generates a postscript file it is actually creating a program that can then be read and interpreted
by another program, for example a postscript interpreter built into a printer, in order to re-create the page.
A postscript printer is just like any other printer only it has a postscript interpreter attached that enables it to understand postscript programs/pages.
All modern offset printing is based around postscript.
You don't need to understand the postscript language as postscript support is built into every modern operating system and
is handled for you automatically behind the scenes. However, you should appreciate that a postscript page is usually a very
complex program and programs can contain bugs - this is why good proofing practice is essential !!
EPS and PDF files are modified forms of postscript and so can never be infallible either.

How are Postscript files produced?
Usually by printing to a postscript printer with its output set to print to a disk file.
You do not actually need to have a postscript printer in order to be able to do this. All that is required is that
you have a postscript printer installed on your system. This is usually done by selecting a "ppd" (postscript printer description) file
from a list supplied by your OS and pressing the install button. If you are intending creating postscript files for offset
printing then you need to select a printer with the following characteristics :-
    Resolution : capable of 2400dpi and above.
    Page Size : Allows you to set a custom page size.
    Default Colourspace : CMYK.
    Binary Data : ON. (some printers can't deal with binary data in embedded graphics and so will often trash your jobs)
    Workflow : Composite ie the printer doesn't insist on creating colour separations.

Printer Settings
You need to use the correct settings when printing. Below are some common examples of settings often encountered.
Postscript Level : 1, 2, or 3. 2 and 3 usually being the best options
Image Data - Ascii or Binary : Go for Binary
Printer Resolution : 2400dpi
Virtual Memory : 25000Kb
Bitmaps : Use JPEG compression
Screen Ruling : 175lpi - 200lpi
Separations : Usually composite CMYK - use separations for proofing and spot colour jobs
Scaling : 100% - not print to fit
Fonts : Download as softfonts. Download ALL fonts in document. Don't use font substitution for device fonts
Compression : Postscript files can sometimes be very large. You can compress them with Winzip or Stuffit.


REMEMBER : To add required bleeds and gutters. Convert everything to CMYK that should be CMYK and everything
to greyscale that should be greyscale. There should be no RGB objects in your final postscript file.