If you need to make a decision between litho or digital printing, here’s everything you need to know.
In a nutshell litho printing uses wet ink and printing plates whilst digital printing uses toners on a press similar to a giant office printer!
At their most basic, digital printing is more suitable for shorter runs and litho printing for longer runs.
Offset Lithography printing (Litho)
The inked image is transferred from a printing plate to a rubber blanket and then the image is transferred again to the paper. Generally the printing will be done out of the standard four-colour process. This means that the artwork is separated onto four different printing plates and each plate prints a specific single colour – cyan, magenta, yellow and black (CMYK). Together these colours combine to create a full-colour print. Occasionally additional printing plates might also be added to print spot colours.
These may be special inks such as fluorescent or metallic inks or a specific Pantone ink that matches a corporate colour. Similarly, there might be fewer colours used such as two-colour printing where only two specified colours will be printed, and because only two printing plates are being made this is cheaper than four-colour litho.
- A significant area of cost is attributed to ‘making ready’ the job – ie the cost and time involved in making the plates and in running the ‘spare’ material that is required until all the plate images are in register and the job can be run. However, once this is done the cost per copy will be cheaper than digital printing on longer printing runs (ie over 2,000 on flat work and over 1,000 on brochures)
- Printing is not limited to four colour process – special or spot inks can be included to enhance the item
- Litho printing is much better for large areas of solid single colour. The colour comes out smoother and no pixels can be seen. (Remember to add a ‘shiner’ under solid black to make the colour deeper and more intense!)
- The introduction of computers to plate making has resulted in quicker plate making and modern computer controlled presses can speed up the process of colour control and getting plates into accurate register
- As above, a significant area of cost is attributed to making ready the job – ie the cost and time involved in making the plates and in running the ‘spare’ material that is required until all the plate images are in register and the job can be run. Therefore litho printing is not suitable for short-run printing as it is not cost-effective
- The turnaround time is longer with litho, usually a five working-day average. This is because time has to be allowed for the ink to completely dry before finishing and longer run jobs have to be scheduled to run on the bigger litho presses
Digital printing is a four-colour process reproduction method that uses electronic files (such as PDF artwork) and dots of colour to produce an image using toner or ink. Unlike litho printing no printing plates are required and there is less waste of chemicals and paper because no ‘make-ready’ is required.
- The finished product does not have a coating added which acts to extend the longevity of the product and protect it from marking and scuffing
- Digital printing using toners can mean that there is some cracking when a job is creased/folded
- Digital printing using toners can result in lamination bubbling or not adhering properly. Problems may also arise with additional processes like spot ultra violet (UV) or foil blocking
- Litho printing will reproduce tints, gradients and large solid areas of colour better than digital printing
- It is very cost effective for small print runs because there is less initial setup involved
- Quick turnaround as the job is produced in its finished format with no additional drying time required
- In many cases jobs can be personalised as they are printed with variable data – such as a sequential number, name or address
Other considerations when choosing between digital or litho printing:
- Weight of materials.
In general most digital presses will run paper weights between 80gsm and 300gsm, whereas litho presses will happily run from 60gsm up to 500gsm.
- Types of materials.
Digital presses are more limited in the types of material on which they can print successfully. Some heavily textured materials do not print very well and gloss papers can also end up a bit ‘flat’ if there is full image coverage. Litho presses have a much wider choice of materials available which are generally cheaper if selecting a specialist stock.
- Run length.
Digital presses are more suitable for shorter run lengths, generally from a single print up to around 1-2,000 (although this figure will vary depending on the particular job specification).
- Lead Time.
It is generally accepted that digital printing produces a job quicker than litho printing as there is no job make-ready or plate making required.
Historically, litho printing was regarded as producing the best quality, and while that is still the case for many job specifications, digital print quality is now so good that in most cases it is hard for anyone to tell the difference.
- Range of colours.
If specific spot [Pantone] colours are required to a high level of accuracy then litho printing is the best option.
- Personalisation [Variable Data].
Digital printed items can be personalised. This makes each print unique to the recipient – for example a direct mail campaign could have the name of the recipient incorporated into the design which will increase the response rate.
- Metallic Inks.
Metallic inks do not reproduce very well in digital printing – best stick to litho.
- UV varnishing.
UV varnishing does not sit well on digitally printed products – best stick to litho.