On the tree of corporate printing there are two main branches, digital printing and offset lithographic printing (just “offset” will do). If all you need from this article is which branch of printing is more appropriate for your job, you can skip to the summary.
Briefly, lithography is defined as “The process of printing from a flat surface treated so as to repel the ink except where it is required for printing” (thanks OED).
Modern lithographic printing, in industrial and corporate usage at least, isn’t strictly lithography anymore, but this distinction is semantic. The “offset” part of offset lithographic printing comes from the indirect manor in which the ink moves, not directly from the plate cylinder (which houses the image to be printed, etched into a “plate”, see diagram below) to the paper, but from plate cylinder onto the rubber coated “offset” cylinder and then onto the paper.
Each colour in a print run needs to have a separate plate, so for a standard 4 colour job (these four colours are what make up the basic spectrum of printed colours–your printer will love you if you say “4 colour” instead of “full colour”) you’d need four plates. Not all jobs need four plates though, and in a bit to reduce costs, many high volume orders are printed with as few as one colour, but usually at least two.
The 4 inks that make up the that spectrum of colours are cyan, magenta, yellow and black (black isn’t technically a colour but again, semantics) and these are often represented by the letters CMYK and are also referred to as process colours. We wont go into this too deeply, but here’s a great article by the authority on printed colour, Pantone, that talks about some of the finer details of achieving colour in print.
Digital printing is more technically complex than offset and comes in a variety of formats. For this reason it’s easier, if you’re interested, to direct you to this informative PDF produced by Techne Graphics Inc.
This brings us to the important question, “which method of printing is suitable for my job?” Unfortunately this isn’t always cut and dry, but if you consider the points below you should have a pretty good idea of which print method will suit your job. When in doubt, consult your print operator.
- Perfect for short runs.
- Fast turn around (plates don’t have to be made, and setup is almost instantaneous, assuming your file is print-ready).
- Variable data capability (this means if you are printing, say, lots of different addresses as you would in a mail merge, it would not be cost effective on an offset press as every address would require a new plate).
- Unmatched stock compatibility.
- Uncompromising colour fidelity.
- Cheaper for long runs (thousands to millions).
- Compatible with Pantone, spot colour or other specialty inks.
- Greater printing quality with higher possible detail.