The Next Big Thing for Flexo

Guest article by David Galton, the European Sales Director of Asahi Photoproducts. The corporate company Asahi Kasei is based in Japan and its principle business is rooted in industrial chemicals for hydrocarbon technologies. Galton remains an active researcher and has published numerous technical papers and articles on his research in recent years. He was the past chairman of the EFIA (European Flexographic Industry Association). He is a native of London and has worked within the printing industry for his entire industrial career. 

Flexography has made huge strides in recent years, achieving quality that rivals offset and gravure. And now the technology is poised to move to the next level, making it even more competitive with alternative printing technologies, including digital.

Technologies such as Asahi Photoproducts’ Pinning Technology for Clean Transfer help make flexography more efficient by ensuring optimum ink transfer (meaning less need to stop the presses for wash-up during a job) and vibrant colour reproductions with soft tonal shades fading out to zero. This is especially important as labels and packaging use more graphical – and even photographic – imagery.

Fixed Colour Palette Printing

The next big step toward quality and efficiency for flexography – already being adopted by leading players – is the fixed colour palette printing technique. This approach typically uses CMYK, or CMYK + Orange, Green and Violet or Blue. The latter, also referred to as Extended Colour Gamut (ECG) printing, can virtually eliminate the use of spot colours by matching a wide array of spot colours and delivers better quality than CMYK alone. Some experts estimate that fixed palette printing using seven colours can match as many as 80% or more of the 1,729 named Pantone spot colours.

This means further reductions in press wash-ups, since the same inks are used from job to job. Presses come up to colour faster after plate changes for a new job, reducing makeready time and waste. In addition, it makes it easier for operations to use combo printing – combining jobs from multiple customers or brands into the same run. This not only increases throughput, but it further reduces waste by making more efficient use of expensive substrates.

Another benefit of fixed colour palette printing is a reduction in ink inventories. Flexo printers often have ink inventories with hundreds of special colours, most of which can now be achieved using CMYK+OVG. While certain colours will still require a spot colour ink, the number of those inks required is vastly reduced. This means that, over time, ink inventories can be substantially reduced, regaining space and further reducing costs and improving efficiencies.

Precision Required

Moving to fixed colour palette printing is not as simple as changing ink on the press … there are many factors that must be considered. But the results, both financially and from a quality perspective, that can be achieved make these efforts worthwhile.

The first step is to ensure agreement among brand owner, designer, repro house and converter that the fixed colour palette approach will meet all specifications. While test press runs are one way to prove out its viability, an easier starting point is to use the PANTONE EXTENDED GAMUT Guide which contains 1,729 PANTONE MATCHING SYSTEM colours produced on coated stock using a seven-colour printing process. Stakeholders can quickly determine if a particular colour is likely to be achievable using a fixed palette.

The repro house or internal plate production operation will also play a significant role. The skills required to assess a current spot colour print job, to break a design down and then rebuild it into an effective fixed colour palette solution, are significant.  The repro house or internal operation must be able to build the program with confidence and partner with the printer in the overall team to enable efficient delivery. Using software solutions will make this process easier.  Ideally, with the brand owner and designer on board, designs can be created from the beginning using 7-colour process.

The press must also be profiled, and that profile must then be validated.  The press must be checked for performance, fingerprinted and then tested for repeatability.  There is no point in beginning to print successfully and then slowly falling away over time from the agreed plan as colours drift. Consistency over the long-term is critical and especially vulnerable in a round-the-clock print operation.  This is also where flexo really opens the door to competing in the long run market with gravure, as well as in the short run market with digital.

The ink manufacturer is also a key to success. Obviously, the premium margins achieved on spot colours are at risk for these partners, and there may be some reluctance on their part to get involved in a changed process. However, the volume of demand for fixed colour palette inks can be an attractive proposition for those manufacturers who understand the value to all partners in the supply chain, and tremendous customer loyalty can be built through the supply of consistent inks and coatings.  The ink specification is critical to colour consistency and must be measured and re-measured on each delivery to ensure that the process stays on track.

The next key variable is the flexographic plate. Fixed colour palette printing requires precise registration, consistent dots and controlled dot gain. It requires a dimensionally stable plate that can consistently reproduce and print small dots and is able to produce vignettes that run down to zero. Support for kiss touch printing will also reduce plate wear and extend plate life, further increasing efficiencies.

Finally, in terms of key criteria, all of the usual suspects have to be assessed for their risk of creating variability in the process – anilox rollers should be measured for specification compliance and actual volumetric performance, wearing of the doctor blades should be monitored, and the environmental conditions of the press shop should be recorded and managed – both temperature and humidity should be correct and consistent at all times.

It can seem like the converter is fighting a list of variables here in order to deliver the perfect printed dot, but with the advent of fixed colour palette printing and complementary technologies such as Asahi Pinning Technology for Clean Transfer, the future of flexographic print performance can be delivered today. The benefits outweigh the risks for those willing to invest in the proper infrastructure, best practices and technologies.