Digital Vs Offset Printing
Digital printers are like a super high speed computer printer similar to an office laser printer and offer flexibility and speed for small runs as they require little setup time.
Some of the latest lease model digital machines offer extremely competitive full colour printing and even more competitive black printing. These machines are usually leased and printing is paid for on a volume basis or by each printed page, with a mono or black page being substantially lower cost to a page with any of the CMY colours on it.
Digital printers have the flexibility of running a double sided job or a mail or number merge job all in the one print, have a high quality finish and have a very quick turnaround time. The ability to customise each page means that these printers are used for customising mail merges and direct mail campaigns where you want variable data on each print. As technology changes machines can now also sort, fold, staple and insert all in the one run.
The largest sheet size in digital printing is an RA3 which is slightly larger than an A3 page. Digital machines will usually run paper stock from about 80gsm up to approx 300gsm.
Offset printing is different to digital printing in that it involves large sheets running through a traditional printing press using a spot colour (often black) or 4 colour process (Cian, Magenta, Yellow, K black). The sheets are then cut to size, folded, laminated or further processed to achieve the desired finish.
Offset printing involves some setup time including making printing plates and setting up printing inks, so a smaller quantity print run would probably best suit a digital print machine rather than an offset press.
Offset printing achieves a very high quality print and is very economical once set-up (minimum quantity permitting) due to the ability to run a much larger sheet and combine multiple jobs if required. More time is required to allow for an offset print than a digital print due to set-up, drying and trimming however once the machine is set, high speed and large quantities can be printed with great ease and a lower overall cost per unit.
Most larger quantity letterbox flyers, postcards and A4 brochures are printed using the offset print process. This would start with approximately 500 A4 size and above - so a quantity of 10,000 x A4 would definitely be an offset print job.
Offset is also known as lithographic printing (although it is really a form of lithographic) and has been around for many hundreds of years. As digital printing technology changes, much of the smaller job sizes are taken by digital printers however offset printing still is superior for high resolution printing where fine detail and a more permanent print is required.
Another type of offset printing is known as a web press. This is a large press used to print newspapers and magazines in large quantities. The main difference with a web press is the enormous size difference (these are large scale printers and can be the size of your average 2 bedroom unit) and the fact that the paper is drawn into and through the press on a continuous roll. Very high tech and impressive machines to watch but most likely not used for your local school magazine run.