Jon -

I think there's been some confusion here about the different "flavors" of PostScript files.

In the general scheme of things, most printers can't print the intended result when you feed them a PostScript file. There is software - and/or hardware - available that will "convert" PostScript to something that "ordinary" printers can handle. The "techie" name for the "converter is a RIP - Raster Image Processor.

In the old days - way back 3 or 4 years ago, printers used a rotating drum with a photo negative taped to the inside (or sometimes the outside) of it. As the "picture" was drawn by a light bulb, it exposed the negative in "rows" to produce a rasterized "plate" that could be used for printing, hence the name.

The "big gun" in software "rasterizers" is probably an outfit called Birmy Graphics Corporation. With a "Birmy" specific to your printer (mine is for an Epson inkjet) you can feed in PostScript and get a print. Unfortunately, the software RIP must be specific to your particular printer - general purpose models don't work well, and typical prices are (or were when I last looked) in the multi-hundred $$$$$$ (US) range.

A PostScript capable printer is simply an "ordinary" printer with a "built-in RIP."

The "bare bones" PostScript file is simply a text file with instructions for "how to draw a picture." If you print it to a non-PostScript printer, you will get the instructions -- NOT the picture. For a typical text document the drawing instructions consist of something like "get this font," "make it this big," "go to this point," "place character number xx there," "spray it with ink." (vastly oversimplified, but we're talking concept.)

A general purpose PostScript file is a .ps or .eps. You must use a PostScript capable printer, or some kind of PostScript capable software if you want to print them.

The .eps, or Encapsulate PostScript, file is a special sort of animal. It is a "metafile" in that it contains the PostScript information but is permitted to contain a bitmap that can be displayed on a computer screen without additional rasterizing. The "encapsulated" part of the file name means that it is supposed to be a "complete" description of some object, and can be pasted into a larger document without messing the whole thing up too badly.

Some non-PostScript printers will print the bitmap if you send the document to them, but there is no guarantee (or even a "requirement" in the standard) that the bitmap will be a true representation of what the PostScript file will produce when rendered on a "true" PostScript device.

The .pdf, or Portable Document Format file, is technically a PostScript file, but of a very special kind. It is intended to be viewable on virtually any computer screen and to be printable on virtually any printer - provided you use the Acrobat Reader, which is a free download, or some other appropriate software like gsview.

The software to create or to modify a pdf file is not free, but the intended "ordinary" users of the file have no reason to need it - if all they need is to view and print.

It is critical to understanding what PostScript is all about that careful distinctions be made between the different "flavors" of PS files. The distinction between .ps and .eps doesn't matter much to the casual user, but the .pdf is an altogether different - and more friendly - animal.

John