Basically, the only ability of the printers' hardware is to place small (color or black) dots onto paper.
This is what hap-pens when you print a monochrome image. Each pixel in such an image has a black or white
color, which corresponds to a certain printer dot. More often than not, we need to print more complex pages
including gray and color images, with vector graphics and fonts. Obviously, there should be some kind of a
program that converts these complex objects to plain monochrome images which needs printer hardware (this
process is called rasterization). The program which provides this process is called RIP (Raster Image
Processor) and sits inside of any printer. The program accepts certain formats of data, which come from a
computer. In other words, printers speak a specific "language", and currently the three most popular printer
languages are PostScript, PCL, and HPGL.
- PostScript was developed by Adobe Systems Inc., and constitutes the basis for all desktop publishing
workflow. All software created by Adobe is also based on this language. File formats such as PS, EPS,
AI, and PDF are also variants of PostScript with most of our printers based on PostScript RIPs. The
PostScript language is constantly developing with the current version being 3. Our copy machines support
this latest PostScript version.
- PCL was created by Hewlett-Packard Inc. for their LaserJet line of printers. PCL RIP is much more
simple and inex-pensive to produce and operate that PostScript. Nearly all inexpensive laser printers
are equipped with PCL RIPs. PCL is not as universal and feature rich as PostScript and has many compatibility
issues with desktop publishing applications that are specifically designed for PostScript output. The latest
PCL version supported by our black and white printers is version PCL 6.
- HPGL is also designed by Hewlett-Packard for large format plotters. Most plotters still support this
language since it is well suited for engineering applications.
One can send all output of the program to a file instead of a printer. Such files will contain all
commands necessary to print the document. For example, if a PostScript printer driver is used to generate a file,
then a PostScript file (usually with an extension PS) with PostScript language commands will be output. This file
can then be sent to the PostScript printer where a printed copy can be made. Outside software is not needed to
print a PS file since the output is processed by the software in the printer. Not long ago, this was the most
common method to prepare print-ready files for printing in a print shop. This method was not convenient since
there is no way to see what is inside of the PostScript file and these files typically have a huge size. These
limitations were overcome with the advent of Adobe Acrobat software, PDF file format and a new, third version of the
PostScript language.
