What Is InDesign OPI?

OPI can facilitate high-volume, fast-paced design and production.

The Open Prepress Interface creates a prepress workflow in which designers use low-resolution proxies as substitutes for high-resolution bitmaps. A special server hosts both the full-resolution documents and their proxies. At print time, the OPI process automatically replaces each proxy with the high-resolution image it represents. This workflow helps minimize the amount of information that must flow through a network within an installation that includes multiple designers and uses large numbers of images. It also limits the data storage requirements on designers' local hard drives. Adobe InDesign includes the capabilities and preferences necessary to support an OPI-compliant workflow.

How it Works

OPI relies on a three-part workflow set up around a server that hosts producers and consumers. A producer application creates layouts that include OPI comments, which are PostScript language commands that identify high-resolution documents and the proxy images they replace. Prepress software serves as an OPI consumer by reading the OPI comments from proxy images and swapping full-resolution graphics in place of low-resolution files. An image substitution server provides both low- and full-resolution files through a network as an OPI host. In an OPI workflow, Adobe InDesign can function as both an OPI producer and an OPI consumer.

When it Works

An InDesign graphic-arts workflow typically invokes OPI functions when a layout or page goes through a printing process. These processes may result in ink or toner on paper, film or plated output for a printing press, or the document equivalent of either of these options, such as an Adobe Acrobat PDF file or PostScript PS output file. During all prepress phases of design, typesetting and layout, the designer works with proxy images in Adobe InDesign, creating the layout destined for one of these output processes.

InDesign, OPI Import

When you create an InDesign layout in an OPI workflow, you import images tagged with OPI comments. These images may include PDF, TIFF or EPS files created in Adobe Photoshop or Adobe Illustrator. You set your InDesign import options to read the OPI links embedded in the files she places into your layout. These comments identify the full-resolution file that will substitute for each proxy at print time. You can maintain proxies throughout your work or use Adobe InDesign as an OPI consumer to replace the proxies before you commit your work to PostScript output, such as a production-ready PDF document or data stream sent to an imagesetter.

InDesign and OPI Output

If you create proxy-based layouts for OPI workflows, you must take care to send OPI comments along when you print or create output files. Without these comments, the OPI workflow can't make image substitutions and the printed output fails to include them. You must choose OPI-compliant preferences in the "InDesign Print" dialog box to make sure your output includes the right information for image replacement at the server. If you create a PDF document for review, you can use your proxies to minimize document data size so your file remains suitable for email-based distribution or quick download from a document server.

References

• Adobe: Using Adobe InDesign CS5 & CS5.5
• Adobe; Adobe PostScript Open Prepress Interface (OPI) Specification -- Version 2.0; January 2000
• "Real World InDesign CS5"; Olav Martin Kvern, et al.; 2010
• "InDesign CS5 Bible"; Galen Gruman; 2010