Workflow Enhancement

No matter how fast networks get, OPI still performs several important roles. The first is strictly a matter of optimizing capacity use: there is no reason to burden either the network or the page layout workstation with extraneous data. The performance of both declines as the file size increases—exponentially with Ethernet-based networks. (That is, if the file size increases by a factor of two, the performance declines by a factor of four.) As for the page layout workstation, using the high-resolution image data significantly slows down the import process. For example, a 30 MB image will require five seconds to "open" in QuarkXPress at full resolution using Fast Ethernet, but the proxy will open almost instantaneously. If the OPI system runs under Windows NT and there are multiple concurrent users, performance degrades further.

OPI also facilitates efficiency in workflows that reuse the same image repeatedly, a common tactic used in the catalog industry to increase response rates. Importing a high-res image multiple times needlessly taxes the server, the network, and the layout workstation. OPI clearly minimizes the load, especially on the page layout workstation because there is less data to manipulate and print.

Given that publishing is an iterative process that usually requires multiple rounds of proofing before final output, OPI plays a major role in cycle time reduction. When printing to a PostScript proofing device,  the layout application must first convert data from native format to PostScript and then spool it to the RIP for processing. When color raster data is included in the data stream there is a considerable delay, during which the workstation and its operator are completely idle. However, by using the various "Omit TIFF" and "Omit TIFF+EPS" options provided by the page-makeup application, the page can be printed in a matter of  seconds. When using these options, the page-makeup application replaces the image data it would have printed with a set of PostScript comments (see example Aldus comments).

OPI also enables better data management practices. Storing all images on the server makes it possible to implement more efficient and more secure workflows. In addition to minimizing data traffic, storing the  high-res images on a centralized server provides an easy mechanism for logging images into an image database according to predefined methodologies. This enables everyone—including operators and clients—to access images more  easily. The images will always be cataloged according to predefined rules, avoiding the one file/multiple names and many files/same name problems that are possible when images are not centrally stored and cataloged. Obviously,  storing images on the server offers better security than does a distributed approach. First, data can be regularly backed up using popular applications such as Retrospect, BackUp Exec, or Legato. Further, storing  high-resolution images on the server minimizes the chance that an image will be altered or deleted—either accidentally or intentionally. For the same reasons, this practice facilitates revision control when images undergo heavy  retouching to create multiple derivative images. Finally, OPI is the most efficient way to provide clients access to their images over the Internet and other remote-access systems. For the same reasons, it streamlines workflow at the client's site and when clients submit files for processing and final output. While prepress shops have built heavy-duty networks, many designers and publishers are still working on 10Base-T and cannot efficiently handling large image files. OPI also streamlines the submission process when clients return a file for final out-put. For those using ISDN or private networks, the cost to transfer a file is directly proportional to its size,  so it is faster and cheaper to use OPI.