File Preparation: About PostScript

What is PostScript?

Modern desktop design is centered around a programming language called PostScript. It has become the industry standard because it provides a simple link between the desktop publisher and their printer. PostScript is a language for output devices. It allows a common software interface despite differences in hardware platform. PostScript controllers exist for output devices ranging from 300 dots per inch paper printers, to over 6000 dpi imagesetters, for film recorders, color printers and color copiers. Without PostScript, every text formatter has to understand the idiosyncrasies of every vendor's hardware. PostScript is a trademark name of the page description language developed by Adobe Corporation.

This page descriptive language translates objects within a page as a series of points, lines and curves (vectors). A PostScript interpreter within the output device then takes this information and converts it into a bitmap (or raster) image of the page. This raster image processor (RIP) then records (or plots) the image to plate, film or paper.

PostScript laser printers are affordable enough that any designer can have a way to present clear and accurate proofs when submitting their electronic art to printers and service bureaus for high-end imagesetting. Most people who generate documentation for a living (be it ads, manuals, or magazines) use PostScript, as it is a well documented open standard used on Windows, Macintosh, DOS, and UNIX systems.

Encapsulated PostScript is a subset of the PostScript page description language. Vector art that is saved in the EPS format can be easily resized with no detriment to detail. This is accomplished because the elements in an EPS file are represented by lines and bezier curves that can be readily scaled based on mathematical formulas. Each element in the drawing is either a line or closed set of lines. Closed items in the drawing have a stroke width, a stroke color and a fill color.

When an EPS imaged is placed in a layout application, it sometimes appears rough on the monitor due to the information that accompanies the file for the screen image. This is just a rough representation of the artwork and should be regarded as a positioning aid.

Click here to learn how to generate reasonably reliable PostScript files from non-Adobe applications via your computer's PostScript "Print to Disk" utility.

Click here to learn how to generate "Press Ready" PDF files using Adobe Acrobat Distiller™

Click here to learn more about the differences between raster image EPS and TIFF formats.

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