Time to offset the record

14 December 2015



Time to offset the record


Time to offset the record

Offset printing has been used since 1875 for tin and 1903 for paper, and it continues to be relevant today. Compared with other printing methods, it is best suited to producing large volumes of high quality prints in a manner that requires little maintenance and at a lower cost. Other advantages include consistent images and longer plate life. However, it faces competition from digital-print and changing-print production volumes. Converting Today takes a closer look at how offset still thrives.

Offset printing is accomplished through layering different inks: cyan, magenta, yellow and black. Each ink is applied separately by adhering to a metal plate in the imprint of the desired image and then offset to a rubber roll, which is ultimately pressed onto the paper. For digital print, toner is used and each colour is applied simultaneously to the paper without the need for multiple metal plates.

Both techniques can be used in the same project, particularly when variable data printing is needed. By pre-printing the shell of a piece, a buyer can take advantage of the less expensive click rate (the cost to print a sheet) of an offset printer for higher volumes. The variable data can later be filled in with a laser printer, or by inkjetting the address panel.
Since there is no comprehensive guide dictating when to use offset, digital or a combination of the two, there are a few general questions customers should ask to discern the best option.

Cost
Offset printing requires more to set up than digital, as production of the metal plates is one of the necessary steps. It is more cost efficient then to use digital printing for print jobs with smaller runs. Lower set-up costs beat the higher cost-per-click on a digital press. For best results in digital, the run should be about 10,000 - depending on other elements of the piece - such as the need for variable data printing and colour matching. For jobs with quantities exceeding 10,000 - even amounts in the millions - printing offset is usually the best choice. Once the press is set up, keeping it running adds only a minimal cost a piece.

Colour
Colours on a digital press are created with combinations of CMYK colours, just like with an offset press. But when printing offset, you can incorporate PMS, or Pantone Matching System, colours. PMS is a colour system with standardised ink colours used in offset printing. So, a printer can purchase the colour of your choosing to ensure an accurate match for your branding requirements, in addition to the standard CMYK four-colour process. If your branding requires exact colour matching across multiple printed pieces, it may be worth reproducing with a PMS spot colour via offset printing.

Variables
If you're considering using offset printing for multiple versions of a project, then this is where offset might need support. Offset may work depending on quantities, but if the numbers don't make sense for offset printing, it may be time to consider digital printing.

Volume is important too. If this is for a short run, then the costs to set up and run an offset line might be more expensive than digital. When customers consider the time lost with changing lines or print variables, then most will move discard offset as unwieldy and expensive in comparison with digital or other methods.

Ultimately, offset thrives on high-volume static printing. If you are publishing a book, magazine, newspaper or a product that will not change colour or message between the first and 100,000th print, then offline is the simple choice.

What is clear in the industry is that shorter runs and volumes are becoming increasingly popular, and this fragmented market means offset is seeing its share chipped away by smaller runs with less volume and more mobile requirements. This change is reflected in the overall decline in market share of offset processes with digital seeing the most gain.

In conclusion, while it is true that print runs are becoming smaller and that this is causing some to turn from offset to digital, there are still large markets, materials and substrates that continue to rely on offset to deliver their products. Despite the competition, offset continues to innovate and adapt, and will continue to adorn our packaging for years to come.

 

Exclusive Interview

 

This might be a rather grim picture for offset printing in the European market, but it is not necessarily shared by converters, as we learn from Paul Wainwright, director of graphics and design and customer fulfilment at Rexam.

Converting Today: What is the main print technology used in Rexam, and what are the benefits?

Paul Wainwright: At Rexam, we use a dry, offset letterpress which has a number of advantages. Firstly, it is dry so no water is used or wasted. Because we use an offset process, we do not print directly onto the can, but rather onto a printing blanket that transfers the image to the can. This means there is a consistently clear and crisp image printed every time. In the offset letterpress, we use printing plates with raised areas to carry the ink from plate to blanket. This is similar to an old-fashioned typewriter key or potato printing, but done 2,000 times a minute with eight potatoes registered together to create an image.

The main benefits of this technique are quality and speed. Using this process we can print about 2,000 cans a minute and provide our customers with a repeatable final image that makes the most of the substrate we use, which is predominantly aluminium.

 

How quickly can you scale up volume?

We have a fully integrated and digital artwork workflow; so once a design is approved, the same design can be run in multiple plants in the same week and sometimes within hours. We see this on a daily basis, with brands across Europe run in multiple locations at the same time in different plants and on different production lines.

How accurate is your colour matching? How can it be improved?

With each ink specially formulated - we do not use CYMK printing - our customers get a bespoke ink colour. The biggest challenge we face is taking a pantone reference, normally printed on white-paper substrate, and translating this into a colour that not only reflects the brand colouring, but gets the most use out of the aluminium substrate. Electronic colour measurement and subsequent machine adjustment still prove to be a challenge, but with the right resources, this could be the next step forward for can printing.

How relevant is digital as a potential printing technique?

A lot of work needs to be done to develop digital printing for our customers with the volumes involved. With production lines running at over 2,000 cans a minute, speed is an essential part of the process and currently digital printers are not able to satisfy this demand.

What is the latest innovation in your technique and how does it affect the finished package?

Rexam developed patent-pending Editions, which allows our customers to create variants of the same design. This can be either as a promotion, or as a way to personalise the finished package to a group of consumers. Since Editions was launched, we have extended the capability of this process to allow us to print not just text, but fine images as well. This allows our customers to appeal to the consumer.

Where do you see the future for printing?

For beverage cans, the process we use hasn't fundamentally changed for decades, but improvements in ink, coatings, digital workflows, software, hardware and printing plates have developed beyond recognition. The process, speed and the advantages of the aluminium substrate mean that new technology and methods of printing find it difficult to gain a foothold in our industry. I believe that we, along with our suppliers, will continue to improve the process and the materials used in the process. Digital printing I am sure will also make an entry, but potentially as a niche printing method.



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