About PostScript and EPS files

PostScript and Encapsulated PostScript (EPS) files serve as older, foundational formats in professional printing and cross-application workflows. Understanding when and why to use these formats helps you make informed decisions about file preparation, prepress workflows, and compatibility requirements.

What PostScript files are

PostScript is a page-description language that defines the appearance of text, graphics, and images in either a device-independent way or a device-dependent way. When you create a PostScript file (.ps) from InDesign, you're essentially capturing a complete description of your document—including all fonts, graphics, and layout information—in a format that imagesetters and high-end printing devices can interpret directly.

Choose the right method for creating a PostScript file

You can save your InDesign document or book in any of three types of PostScript files: device-independent, device-dependent, or device- and driver-dependent.

The following tables list recommended printer drivers and output methods for achieving the best results with post-processing applications and InDesign. If your document will be processed by an OPI server, or by an imposition, trapping, or other prepress application before it’s printed by a RIP, choose PostScript® File in the Printer menu in the InDesign Print dialog box. That way, InDesign has complete control over the DSC output. For desktop printing, use any supported PostScript printer driver.

The tables use asterisks to indicate the relative suitability of each method for prepress work:

Printer selection: PostScript® File

A printer driver isn’t used when the printer selection is “PostScript® File.”

Printer selection: <installed printer>

The PPD used by the selected printer appears in the PPD text box at the top of the Print dialog box.

Types of PostScript files

InDesign can generate three types of PostScript files, each suited to different workflow requirements:

Device-independent PostScript files: Contain no printer-specific information and work with any output device. These files offer maximum flexibility when the final output device hasn't been determined or when files need to move through multiple prepress applications.

Device-dependent PostScript files: Are optimized for a specific printer, imagesetter, or platesetter. You create these by selecting a particular PostScript Printer Description (PPD) file when generating output. This approach works well for pre-separation or trapping workflows, particularly when you plan to use the automatic trapping features or Adobe In-RIP Trapping.

Device- and driver-dependent PostScript files rely on both a specific output device and a particular printer driver. While these files may work well for immediate output needs, they offer less flexibility for prepress workflows that involve post-processing applications.

When to use PostScript files

PostScript files serve specific purposes in professional workflows. Consider creating PostScript files when:

• Your service provider requests them for direct output to an imagesetter.
• Your workflow includes OPI servers that replace low-resolution proxy images with high-resolution versions.
• Your imposition, trapping, or other prepress applications require PostScript for final output.
• You're working with remote printing services that require PostScript.

For most modern workflows, PDF has largely replaced PostScript files for general document exchange. However, PostScript remains relevant in some specialized prepress environments and legacy workflows.

Understanding EPS files

Encapsulated PostScript (EPS) files are self-contained PostScript documents intended to be embedded in other documents. Unlike PostScript files that describe entire documents, EPS files typically contain single pages or graphic elements.

When you place an EPS file in InDesign, the application creates a low-resolution bitmap preview for onscreen display while preserving the high-resolution PostScript data for final output. This approach allows for efficient editing while maintaining print quality.