Medan vi inom offset haft en fyrfärgsstandard under många år, så finns det fortfarande inte en standard inom flexotryck, som är den dominerande tryckmetoden för förpackningar. Resultatet är att en varumärkesägare mycket väl kan behöva hantera mellan 30 och 50 olika specialfärger, för att trycka. Varje gång en av dessa färger ska läggas i ett färgverk, går det typiskt åt 15 liter lösningsmedel för att tvätta ur färgverken.
I den här artikeln, som är på engelska, går författaren igenom varför problemet finns och inte är lätt att lösa. Men han visar också på hur man, genom att enas om en sjufärgsstandard, skulle kunna uppnå en högre tryckkvalitet, bättre färgåtergivning och spara mängder av små serier med färg. Författaren arbetar själv med Asahi tryckplåt, så han har inga kommersiella intressen på färgsidan.
Achieving Fixed Colour Palette Printing Excellence with Asahi
With brand owner and retailer focus continuing to be placed on cost reduction and improved efficiency, all eyes are on the potential that fixed colour palette printing brings and what it can deliver for the large brands. But it’s not as simple as many might think. Many large flexible packaging companies promote the idea, but very few are actually delivering the solution effectively on a large scale.
What are the benefits of Fixed Colour Palette Printing?
The clear benefit of the process is the reduction of Stock Keeping Units (SKUs) throughout the supply chain. For large brands, the use of 30 to 50 spot colours for a product range is not uncommon. This means increased inventory, more complex logistics, and more purchasing and administrative resources … the list goes on. By reducing the number of inks to a very low number through smart extended colour gamut design, the entire supply chain is condensed from the time the project is submitted for production through end of life, minimizing costs and increasing efficiency.
More importantly, there is reduced waste in the supply chain. Less substrate material is wasted in changeovers and the impact on landfill is reduced. There is also approximately 15 litres of solvent used in each colour wash-up on a typical flexo press. This is eliminated, creating a large dent in the emission of VOCs, which reduces the manufacturing carbon footprint of the plant. And, of course, by being able to produce packages in smaller lot sizes, there is less waste when products become obsolete or are no longer able to be sold.
But it is not all about cost reduction and the environment, although these are certainly important. The, perhaps not unsurprising, benefit of moving to a fixed colour palette process is the improvement in print consistency. For every spot colour you bring to press, you bring a potential for colour drift and variation from the specification.
Ink manufacturers pride themselves on delivering inks that meet customer and application needs, but it’s clear that variability still occurs. Many pigments in flexo inks vary in purity and specification dependant upon where they are sourced, and accurate, repeatable ink formulations can be complex. Ink companies also secure global sourcing networks to guarantee supply, making it even more likely that inks will vary on press too frequently.
With fixed colour palette printing, the press operator does not have to “tweak” the spot colour to achieve the performance desired. It is understood that spot colours can drift more than the standard fixed process colours, which requires constant management. With process colours, it is actually easier to control the colour. Of course, this also has its downside. The brand owner must spend quite a bit of time and energy up front on the product portfolio, agreeing to the colours and specifications … and once it’s fixed, there is no going back.
But there is a considerable upside as well. Due to the way fixed colour process printing works, there can be higher perceived brand colour performance. Since the colour put down in layers, as opposed to a spot colour simply being laid down from a single cylinder, homogeneous solid colour performance can be achieved without hickies or printing pinholes due to the ink overprinting in multiple colours. Prints with the addition of orange, green and violet (or blue) are more vivid. Photographic imagery with punchy, vibrant colours can be achieved with expanded colour gamut.”
In fact, the truly exciting part of this process is the ability to combine these more striking colours in ways that drive pack premiumisation and market differentiation. Alternatively, by using a fixed colour palette with four colours, only a small number of colours are needed for the job. The press then has a number of redundant decks that can be utilised for specialist inks and coatings such as thermochromics, pearlescents or tactile coatings. This results in simplified printing, even for complex designs, with an opportunity to increase pack differentiation and value at an optimum cost.
Fixed colour palette printing is less expensive to execute, but it can truly differentiate a pack on shelf at the same cost as the traditional spot colour methodology.
Finally, in terms of benefits, speed to market for new designs in the product line should also be considered. When a new pack emerges in a brand portfolio, the materials will already be on site to produce these new pack designs. This means shortened lead times for brand owners once the project reaches the print stage.
To sum it up, there are accumulated savings across the supply chain when utilising fixed colour palette printing, from concept to consumer that should not be ignored in a highly competitive marketplace.
What are the critical parameters for effective delivery?
It’s clear that fixed colour palette flexo printing is not simple to achieve. Every variable in the press shop has to be considered if the consistency and quality of the printing is going to be maintained.
First and foremost, the brand owner has to take control and agree on the design and colour specifications up front, and the expectations of the client then have to be managed by the flexo shop. This is not a short process. Significant effort, and indeed some flexibility, is needed on both sides for a serious fixed palette programme to be successful. On the flip side, the benefits that can be accrued are enormous if everyone in the process understands the frame of operation and the limits of what it can and cannot do.
A specialist reprographic house must also be involved. 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 must be able to build the programme with confidence and partner with the printer in the overall team to enable efficient delivery.
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 will likely 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. As stated earlier, 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. Asahi Photoproducts has specifically developed its Pinning Top Dot flexographic plate series to take best advantage of the cost efficient fixed colour palette printing process. Asahi Pinning Top Dot (PTD) technology is incorporated in the AWP™-DEF, AFP™-TOP and AFP™-TSP plates.
The Asahi PTD plate solution delivers high quality, vibrant colour reproductions and soft tonal shades fading out to zero. PTD technology allows a ‘kiss-touch’ printing pressure setting to be used, which enables constant repeatability of printing during the production run and prevents excessive ink laydown or accumulation on the plate; again driving further consistency in the fixed colour palette system. Pinning Top Dot technology also reduces ink filling-in of the mid tone area over a printing run, leading to further savings for the printer in reduced cleaning intervals and less press stop downtime. Furthermore, PTD technology is delivered via a plate solution that easily fits into existing wide and narrow web flexo printing environments without the need for additional equipment investment. The Pinning Top Dot plates also feature excellent compatibility with commonly used solvent, UV and water based ink systems on film and paper substrates. This flexibility enables the printer to react to changing market needs while keeping the business environment sustainable and cost effective.
As an example, of the enormous quality achievement of the Asahi PTD plate solution was recently honoured by the South African FTA award ceremony. Packages printed with the AFP™-TOP plate was repeatedly honoured for the second year in a row with the “Best of Show” award in addition to gold awards in two other categories. The comment from the Judges were: “as close as you can get to perfect”.
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 printer 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 Top Dot technology, 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.
The information in this article has been gathered in cooperation with a leading Fixed Colour Palette UK flexible packaging printer who would like to remain unnamed.
by Dr. Dieter Niederstadt