What is the difference between litho and digital printing?

The main difference is that litho printing uses wet ink and printing plates, while digital printing uses toner on a press similar to a very large office printer.

Digital printing is better for shorter runs, while litho printing works best for longer runs.

How does offset lithography (litho) printing work?

During offset litho, the inked image is transferred from a printing plate to a rubber blanket, and then to the paper or card by the standard four-colour process. This means that the artwork is separated into four different printing plates and each plate prints a specific single colour – cyan, magenta, yellow and black, also known as CMYK. These colours then combine to create a full-colour print.  

Depending on the job, you may need additional printing plates to print spot colours, which are special inks such as fluorescent, metallic, or a specific Pantone ink that matches a corporate colour. If a specific Pantone colour is required to a high level of accuracy, then litho printing is the best option.

Can you tell me more about litho printing?

A large proportion of the cost is ‘making ready’ the job. This includes the cost and time to make the plates and run the press until all plate images are in register and the job can be run. Once this is done, however, the cost per copy on longer print runs, such as 2,000 upwards on flat work, and 1,000 upwards on brochures, will be cheaper than digital printing. Litho printing isn’t suitable for short-run printing, as it isn’t as cost-effective as digital printing.

Printing isn’t limited to the four-colour process (CMYK), as special or spot colour inks can be included to enhance the finished result. This is especially noticeable with orange: as a spot colour, it looks great, whereas CMYK produces a muddy brown hue.

Litho printing gives much better results for large areas of a solid single colour, as the colour comes out smoother with no banding. Traditionally, in pre-press, when film was used to make plates, a 40 or 50% cyan tint was added under the solid black, known as a ‘shiner’, to make the colour appear more intense.

The introduction of computer-to-plate making (CTP) has made plate making much quicker and, coupled with modern computer-controlled presses, can speed up colour control and getting plates into accurate register.

The turnaround time is usually longer with litho, normally 5 working days. This allows time for the ink to dry completely before finishing. For longer runs, it may need to be scheduled on larger presses.

Let’s have a look at some of the plus points and negatives of digital printing.

Digital printing is cost-effective for small print runs because it requires less initial setup. Because no printing plates are needed, wastage is lower, as ‘make-readies’ are not required.

Quick turnaround is possible as the job is produced and ready to go with no additional drying time required.

• Digitally printed jobs can be personalised as they are printed with variable data – such as numbering, names, addresses or contact details, making each print unique to the recipient; i.e. a direct mail campaign could have the name of the recipient incorporated into the design to make it more personal to them.

• The finished product doesn’t have a coating applied over the print, such as a sealer; it can be prone to marking and scuffing. 

• Digital printing using toners can cause cracking when a job is creased or folded, which can be more noticeable on thicker stock such as card. It can also result in lamination bubbling or not adhering properly across the crease.

• Digital printing won’t reproduce tints, gradients and large solid areas of colour as well as litho printing.

You may also want to consider other factors, too.

What material weight can I use?

As a rule of thumb, most digital presses will run paper weights between 80gsm and 300gsm, whereas litho presses have a much wider range, anything from 60gsm up to 500gsm.

What type of material can I have?

Digital presses are limited in the types of material onto which they can print. Some textured materials don’t print well, and gloss papers can also look a bit flat if there is a large image coverage. Litho presses offer a much wider range of materials, which are generally cheaper if you need a specialist stock.

What is the run length?

Digital presses are better suited to shorter runs, generally from a single print up to around 500-1000 copies, whereas litho presses can run anything from 1000 upwards.

What is the lead time?

If time is critical, digital printing produces a job faster than litho printing, as it requires no job make-ready or plate-making. You could always start with a small digital run, then print a longer run litho as time allows.

What is the quality like?

Litho printing has long been regarded as producing the best quality. While that is true for many job specifications, digital print quality is now so good that, in most cases, it is hard to tell the difference.

I hope you found this article useful, but if you would like more information, please ask.