Custom Printing: What Is a RIP and What Does It Do?

I think it’s fair to say that a RIP is one of the more important elements of a successful commercial printer’s prepress workflow. A RIP translates the arcs and curves of PostScript code into a matrix of dots that can be printed by the custom printing vendor’s platesetter or imagesetter. It is a universal translator, a Rosetta Stone for printers. It can print the pages you compose in InDesign or Quark, or if your files are not created appropriately, the RIP can choke and not print your work.

A RIP in More Detail

The fonts and graphics in your page composition software are composed of Bezier curves. These are mathematically defined arcs that will be of the highest resolution possible when printed by the target imaging device. A 600 dpi laser printer will print the text at 600 dpi, while a 2400 dpi platesetter will print the same file at this higher resolution.

The imaging device (laser printer, imagesetter, or platesetter), however, does not understand PostScript code. Therefore, the “vector” code of lines and arcs must be rendered into a fixed pattern of dots on a grid, a “raster” image. A Raster Image Processor, or RIP for short, does exactly this.

RIPs come in a variety of flavors. Some are dedicated hardware devices that come with the imagesetter or platesetter.

Other RIPS are firmware, built into the printer’s circuits (a laser printer might have such a RIP).

Finally, some RIPS are software only, and they can be used with a number of different printers. For example, if you buy an inkjet printer, you will also need to buy a software RIP if you wish to print out the complex graphics (EPS images and such) created by your PostScript software. (In the case of high-end inkjet proofing devices, however, the RIP—either hardware or software—may come bundled with the proofer.)

Sometimes There’s No RIP

In some cases you might not have a RIP at all. Instead, you might rely on a printer driver to allow the originating application to communicate with the destination printing device. This may be fine, but if you are producing complex documents, you will probably need a RIP, and if you just want added functionality, you may also want a RIP.

For instance, unlike a printer driver a RIP may add these additional capabilities to your commercial printer’s workflow:

1. A RIP can collect and process a group of print jobs (known as a “queue”) and batch process these files while freeing up your computer to do other creative work. Offloading this task will keep your computer from slowing down while you do page composition and also keep your printer from slowing down or ruining your print job with artifacts or banding. (That is, when a computer must switch between two complex processes–printing and page composition–quality and speed will suffer in both cases.) A RIP takes the load off the computer.
2. A RIP can handle imposition (placement of pages on a press sheet so that the sheet will have all the pages in the correct order when it has been folded and trimmed).
3. A RIP can handle trapping (the adjustment of design elements to create a slight overlap where items of different colors touch one another, so that if the job is printed slightly out of register, there won’t be white lines between the colors).
4. A RIP can handle color separations (breaking a 4-color image into separate cyan, magenta, yellow, and black printing plates) and halftone screening (simulating different shades of a color with screens made up of grids of larger or smaller halftone dots).

How to Avoid Problems with the RIP

Here are a few potential problems with RIPS that you may want to consider while you build your design files:

1. Large files slow down a RIP. Therefore, simplify files where possible. Do not leave elements on the pasteboard (area around a page). Also, crop images in the photo editing program rather than the page composition software (Photoshop rather than InDesign). A portion of an image hidden by an InDesign picture box will still add to the size of the file and therefore lengthen the RIP’s processing time. Also avoid nesting one file in another (an EPS in another EPS, for instance).
2. Keep in mind that not all RIPs are created equal. A PostScript Level 3 RIP will do more than a Level 2 RIP. Your file may need capabilities not built into your commercial printer’s RIP. So ask your custom printing vendor about his RIP level and its compatibility with your design software.
3. Corrupt files or fonts will stop a RIP in its tracks. If you get error messages, you may need to rebuild the file, save it under a different name, or replace fonts that have become corrupted.
4. To avoid both RIP compatibility issues and corrupted graphics or fonts (or problems with overly complex graphics), a good rule of thumb is that if the job cannot be printed on your laser printer, it won’t RIP properly on your custom printing vendor’s equipment. So test the document before you upload it to your commercial printer’s FTP site.
5. InDesign and most other page composition software packages will include a limited array of preflight tools. Dedicated preflight applications will have even more preflight capabilities. Get in the habit of checking your files before submitting them to your custom printing supplier.
6. Before you use TrueType fonts, make sure your printer can handle them. In addition, don’t mix Type 1 and True Type fonts in a single document.
7. Distill your PDF files with Adobe Acrobat Distiller, not PDFWriter.

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This entry was posted on Saturday, March 24th, 2012 at 11:53 pm and is filed under InDesign Software, Prepress. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.