That has meant, for many flexo packaging producers, that the use of spot colours has been necessary to achieve the exact shade of whatever the brand owner requires.
In recent years, however, brand SKUs have proliferated while product lifecycles have shrunk, and this has driven costs and complexity upwards.
But has flexo printing technology reached a point when smart repro, platemaking, anilox and ink developments mean that fixed-palette printing (FPP) – even down to a standard four-colour ink set – is now a realistic option?
Hybrid Software’s Paul Bates finds it a tempting proposition: “You open Pandora’s Box with fixed-palette printing. Once you start along the process, it is natural to think ‘If that’s what can be done with six or seven, then what could we do with four?’”
Perfect storm
Hybrid develops productivity software solutions for graphic arts businesses and Bates says “there has been a perfect storm” in packaging and flexo technology assisting this move. This is echoed by Emma Schlotthauer, Kodak Flexographic Packaging Division worldwide marketing director, who says: “High performance flexo plates have been crucial in delivering multiple factors that have enabled FPP. Fixed palette is not an option without higher density and better ink transfer.
Bates adds: “HD flexo has increased the colour gamut possible out of CMYK phenomenally – 20% colour gamut gains – through higher density/thicker ink films.”
Dieter Niederstadt, technical marketing manager of Asahi Photoproducts (Europe), agrees that platemaking and anilox technology have come on in leaps and bounds: “Hybrid screening has enabled smooth gradation down to zero and smoother tints and vignettes.” He also points out that line screens have increased from a standard 120lpi up to more like 150-175lpi as standard, and even 220lpi for some applications.
“Anilox is another area where developments have helped,” says Niederstadt. “Apex has its free flow technology – linear channels for the ink rather than hexagonal cells, which ensures a more homogenous transfer – and other manufacturers are also developing alternative cells structures.”
Something else that Asahi has been working on is modifying the plate surface to ensure a more complete ink transfer. “Think of it as being like the non-stick coating on a saucepan,” says Niederstadt.
In May this year, Bobst unveiled its THQ Flexo Cloud process, intended to challenge laminated litho print in the secondary packaging market. The process requires a higher line screen on the plate with a matched anilox roller and is said to achieve 65% of the Pantone gamut. Bobst Lyon sales & marketing director Dominique Ravot says there are two main opportunities: “Firstly, offering higher quality compared to other post-print flexo operations; and secondly, to attack lower end litho lam with lower cost.”
Bobst says its system is purely intended for post-print corrugated, but the principles are valid for any flexo process.
Alongside these, ink manufacturers have modified the weight of pigmentation and the drying characteristics of their inks. Tape manufacturers have developed their products too to ensure better ink transfer through the optimisation of the hardness and the rebound. And flat-top dots are now used to boost ink film density.
But perhaps the field in which the most important impact has been made is in process control. After all, FPP isn’t a new concept in flexo printing. Pantone’s own Hexachrome system, which added orange and green to the standard CMYK ink set, was introduced around 20 years ago, as was Opaltone, a system that combined the CMYK ink set with RGB colours. Flexo, however, wasn’t consistent enough to capitalise on either system, says Niederstadt, adding that “in the last few years it has become much more stable”.
The science bit
In other words, if you’re not taking a scientific approach to managing colour FPP won’t work for you. Print operators managing colour on the fly just won’t cut the mustard – FPP requires a different mindset.
Mark Gundlach, solution architect at X-Rite, says: “Changing from running spot to process is a new challenge. FPP has to be built on standardised processes and process control. I still run into shops using visual matching – they’re matching to a colour chip and changing the impression to get lighter or darker and adding red or green to the ink to adjust the colour.”
Kodak’s Schlotthauer says: “In FPP everything is a build, and especially with lighter colours using smaller dots. You need consistency and repeatability. If you can’t deliver gamut and small dots consistently it is a non-starter.”
Bates says understanding spectral data is crucial. Brand owners may be persuaded to accept an imperfect colour match, if it’s close enough and comes in significantly cheaper. “You can review decisions based on the ‘delta E’ measurement with the brand owner. It enables them to make informed decisions.”
Gundlach adds: “You’ve got to manage dot gain, so you’ve got to pay more attention to the anilox and the sticky back. You need to have the right anilox available.”
Press profiling is essential to assess exactly what colours are available within the fixed palette, and the use of spectrophotometers and densitometers will have to become more prevalent for FPP to be successful.
But the challenges are not purely technological but interwoven with the nature of the packaging sector, which is famously cautious. Kodak’s Schlotthauer explains: “The packaging industry is somewhat risk averse and has a very long supply chain, and as fixed palette printing affects everyone from the brand owner, through the designer to the printer it is a challenge to get everyone on board.”
John Anderson, global business development director at Kodak’s Flexographic Packaging Division, says: “Customers who are successful see it as a complete change in manufacturing. You won’t get there without the technology but you won’t get there without the right mentality either. You need to champion it to your clients.
“And there may be some colours brands are very reluctant to move away from – especially if it is the dominant brand colour. In that case you may end up producing in CMYK with one special. Often that colour will be achievable within four-colour but it’s a question of brand confidence.”
And it’s not just about time and cost savings, it’s also about enabling new opportunities. Schlotthauer says: “If you have an eight-colour press and you’re running six or seven colours there’s not much option to add effects.
“But if you’re running a four-colour job there are four decks that can be used for other processes such as varnishing, embossing and foiling. You can offer all of those without the expense of investing in a new press with additional units.
“It’s a way of adding value without incurring capex.”
Anderson adds: “Flexo can now print better than offset for folding cartons. One big advantage with roll-fed flexo is you can do away with the 8% waste needed for the gripper margins on sheetfed offset. When you are throwing away 8% of the most expensive component of a job away you can get a very good pay-back.”
Case study: Mercian Labels
Mercian Labels is a firm that, in combining flexo and digital production, has experienced many of the challenges around moving to FPP. The Staffordshire firm has standardised on CMYK across its flexo and digital kit, while offering spot colours in addition to CMYK on its flexo presses. The primary driver for its approach is to be able to match and switch jobs between digital and flexo as simply as possible when required.
“Our Xeikon only has CMYK plus white, so if you need digital you have to accept a compromise,” says managing director Adrian Steele. “On flexo we can stick to CMYK and add a spot colour as needed. We have standardised on Fogra 39L and do a lot of colour management to ensure the colour consistency of both flexo and digital CMYK.
“Customers don’t care how it is made, they want quality, lead time and service. You can create more efficiency if it is easier to switch between the two. The driver is turnaround times and number of SKUs.”
Steele is assessing extended colour gamut (ECG) printing, including the Revo ‘digital flexo’ initiative, however he is currently unconvinced that the technology is right for the markets that Mercian operates in.
