First of all, if a file is coming from Photoshop it does not need to be “ripped”, it is already a raster image file. Newer versions of Photoshop serve as a very effective RIP in a variety of applications. For many low production environments, Photoshop and a little ingenuity is all that is needed. Try saving a file as an EPS from whatever vector application you are using and open the EPS file (it’s Adobe legal) file in Photoshop at the size you want and presto, it’s been ripped.
I am amazed at how fast Photoshop can complete this job. It’s becoming a poor man’s Rampage or Scitex workstation. RIP stands for ‘raster image processor’ and I would really like to see the term confined to that definition otherwise it leads to endless confusion. For vendors, confusion is useful as it allows them to sell more stuff. For end users, confusion may lead to unnecessary expenditures for software and hardware. Strictly speaking, raster image processing means turning a bunch of equations and commands into pixels that can actually be printed. That’s it!
Occasionally you get printed output that is a bunch of gobbledygook in which case the interpreter has lost its mind and is passing on the code directly to the printer. So a RIPs basic job is to take vector graphics data and convert it to bitmapped graphics. Expand this definition to PostScript RIP and you introduce the ability to handle four channels of bitmapped data to what a RIP does (as well as a host of other things, further complicated by the level of postscript compatibility the RIP was designed for: Level 2, Level 3, etc). Simply put, this means you would need a PostScript RIP if you need to pass on your CMYK definitions of ink limiting and K generation on to an image setter, plate setter or direct digital press. You actually can’t drive these things without one.
For most modern Epson printers and the like, the RIPs driving them have to take this incoming four or three or one or six whatever channels and reconvert it for the six, seven or eight colors actually being applied to the paper, thus somewhat diluting any ink limiting or K generation intended by the user who originally created the CMYK file. How this is done varies from RIP to RIP and is not often well explained. This is why you will hear that it is best to see these printers as RGB devices. Epson drivers are calibrated and profiled for RGB input and perform much better when presented with RGB images. RIPs on the other hand, are profiled for CMYK and (with the exception of a few RIP’s for RGB photo applications, Best, Colorbyte) perform best when dealing with CMYK files.
Incidentally it is important to note that this print driving function has absolutely nothing to do with raster image processing. For instance the Epson driver is not a RIP but it can take a wide variety of incoming data and drive the printer. Confusion is increased by the misuse of the term RIP to include print spooling, icc profile conversions, printer drivers, etc. You don’t need a RIP to do any of those things, although good RIPs can vastly simplify their application. Some RIPs include these functions while others do not and some implement them better than others.
If you need print spooling, try using USB printer share under Mac OS 9 or Printer Sharing in OS X or Windows before you run off and buy a RIP. This works exceptionally well if you have an older computer kicking around (iMacs are great for this). Set up the computer to share the printer, connected either via network or USB, and you can send the files to that computer for printing. This leaves your primary workstation with more processor headroom for stuff other than printing. If you need advanced printer driving, try GIMP print that is free (and includes a free PostScript emulation interpreter) or ImagePrint, which is often referred to as a RIP but in its base version, most certainly is not. If you have an Epson 2200 and OS X already up and running, the $500 for ImagePrint or I-Proof is a pretty good deal and getting better by the day.
If you want to introduce an icc compliant workflow, it’s already there in Photoshop, Live Picture, LinoColor, ImagePrint, ColorBlind, In Design and no doubt many other applications. You certainly don’t need a RIP for that and in most cases other applications do the job better and with more flexibility anyway.
With inkjet printers, a RIP could also benefit the workflow by:
• Correctly map colors from one space to another, smaller CMYK colorspace, for prepress proofing (with raster image files, vector image files and Postscript files).
• Correctly map colors from an RGB or Lab color space to the printer’s native colorspace for the widest range of useable color.
• Lay down picoliter ink droplets in a manner that achieves photographic quality better and/or faster than printer drivers included with one’s printer.
If you need help when determining whether you need a RIP or not, please call me at 800-268-2969, ext.116.