Page 193 - Graphic Design and Print Production Fundamentals

6.6 Page Description Languages

Roberto Medeiros

Many page description languages (PDL) exist today; however, Printer Command Language (PCL) and
PostScript are the most common and widely adopted. Each has its strengths, weaknesses, and jobs for
which it is best suited. It is important to understand these differences and choose the method best suited
to your particular printing requirements.

PCL

PCL is a page description language developed by Hewlett-Packard (HP) and was originally used on HP
impact and inkjet printers. PCL 3 was the first version to be used with a laser printer, the HP LaserJet,
released in 1984, around the same time PostScript was introduced. The goal of PCL was to have an
efficient printer control language that could be implemented consistently across HP’s printer line. Simple
commands and functionality would not require expensive print controllers, making it very attractive for
utility-level printing. Many other printer manufacturers implemented PCL for this reason. Commands
are embedded at the beginning of the print job and set the parameters for the printer to use for the job.
These commands remain set until a new value is assigned for the command or the printer is reset. If the
printer does not support a specific command, it ignores it.

When colour laser printing became available, PCL 5c was developed with similar goals. New commands
were added to the existing command set, as was the case with all the predecessors, to add support for
colour printing. This ensured backwards compatibility while minimizing development. When it came
to colour, HP’s goal was to have colour on the printed page look the same as what was displayed on
screen. There were many challenges to achieving this, so print quality adjustments were included to
give users the ability to fine-tune the output. With the emergence and widespread adoption of the sRGB
standard to define and describe colour on a display, the PCL colour command set could be simplified
by adopting this standard for colour printing. Thus, HP’s goal could be achieved without the complexity
and overhead of a full colour management system. Operating systems and applications, for the most part,
have standardized how they display colour in sRGB, so this approach is the simplest way to achieve
acceptable colour between display and print. PCL is most appropriate for general office use where a
simple, low-cost print device that produces good quality colour is expected. It is not suitable, however,
for a colour critical or print production environment where precision and full colour management is
required.

PostScript

PostScript is a page description and programming language developed by Adobe that describes text,
graphics, and images, and their placement on a page, independent of the intended output destination.
The code created is in plain text that can be written and examined with a basic text editor. The output
itself can either be to a printer, display, or other device possessing a PostScript interpreter, making it

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