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Introduction to Raster Image Processing

(February 2002) posted on Fri Mar 01, 2002

Find out how RIPs operate and what benefits they offer.

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By Mark A. Coudray

Two primary types of RIPs are available: hardware and software. A hardware RIP is a dedicated piece of computer equipment with an application specific chip-set designed to optimize the processing of graphic files. Such RIPs are usually bundled with specific output devices, most typically an imagesetter. But this is an older configuration and is generally found in first and second generation RIPs. They are usually closed architecture, meaning that we can't access the software directly, other than through routine maintenance functions.


The more modern approach is the software RIP. Here the imaging software is loaded onto a dedicated server. The server could be any high-end Mac, Windows NT or 2000, or UNIX box. Often the machines will have multiple processors to divide and expedite the billions of calculations necessary to rasterize an image.


The architecture is typically open, which means we can add functionality to the software as we need more capability. This will become more apparent later when we discuss all of the things that the RIP software can offer. With a software RIP, we can often purchase the RIP separate from the imaging device. The RIP just processes the image and then directs the digital flow to whatever device(s) we have specified.


RIPs include features to support both image and workflow processing, such as job queuing, open prepress interface (OPI), image caching, time processing, and production logging. The job queue functions allow for multiple users to send images to the RIP simultaneously. The jobs are spooled and held in a print queue for imaging.


The RIP operator has the ability to allow jobs to arrive in the queue, to print in the order they arrive, or to delay or expedite jobs within the queue as necessary. These capabilities can be very useful when only one separation needs to be rerun due to an error or a problem on press. Very large or complex jobs can be scheduled to RIP on the second shift, or even at night when intensive processing will not interfere with smaller jobs needed during the day.


OPI-type RIPs allow for placement of low resolution images for position only within the digital document. The displayed graphic has only enough resolution to be viewed properly on the computer monitor.



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