As first seen in https://www.flexography.org/industry-news
Why Proofing Matters- John Rastetter. Pamarco and Jeff Ashburn. Flint Group
The importance of color and the need for accuracy of reproducing color in packaging today cannot be overstated. The increase of brands in our market means that colors must match perfectly in order to maintain buyer recognition and loyalty. The only way to accomplish this goal of color consistency is to focus on ink standards and ensure that the package on the grocery store shelf matches the targeted color regardless of the type of substrate. After all, it is the identity of the brand being represented on that package, so perfection is the only option.
Of course, we all know that perfection isn’t always the outcome. Challenges occur along the way that interfere with our goals. Because of this harsh reality, it is necessary to deepen our understanding of ink and how to achieve that ideal color. In this paper, we will investigate the means of achieving color consistency in any situation through the use of ink proofing. To do so, we will cover the steps involved in ink proofing and discuss its importance to print. We’ll also include a special focus on Iris, Pamarco’s automated proofer, and explain how it can help you get the color you want with every print job.
When focusing on the significance of hitting color targets on all substrate types, it helps to think about brands that have mastered the skill of consistently recognizable color. A global brand must have consistent color regardless of the manufacturing location, and their packaging must be produced using the same formula and action steps. There must be accurate reproduction on a variety of substrates, on multiple types of equipment, run by varying people, using many different processes in all types of environments. With that kind of laundry list, how does anyone manage to get repeatable results?
Before we dive into the specifics of accurate reproduction, let’s begin in the shallow end with a quick review of the moving parts behind ink. The first priority is that ink must arrive at press side ready to run: that means meeting the LAB, dE and density requirements. All ink manufacturers have quality control procedures that include ink proofing technology, allowing them to meet brand owner requirements for color. The printer receiving the ink also has proofing technology to ensure the correct color match on site. But what happens when ink proofing procedures are not followed or are not performed consistently?
When ink arriving at press side isn’t the correct color, printers find themselves with color density outside of the needed range. In other words, it becomes a problem detectable to the naked eye. Sometimes operators notice before it’s too late and are able to make adjustments. But press time is costly, so even minor changes can be an expensive undertaking. Waste of time, waste of substrate, waste of consumption…the list of possibilities is long, not to mention the customer relationship strain during a long press OK, and/or the rejection of the job entirely. Even just a few extra minutes of make ready time that is associated with ink can be very costly on an annual basis, especially when press time costs $600/$800/$1,000 an hour – that can quickly become an expensive proposition. Some figures for example:
4 jobs a day
5 minutes saved per job
Press time: $800/hr or $13.33/min
Annual savings: $97,000
In order to avoid these issues and to those annual savings, we need ink that is pleasing to the highly accurate instrument most of us innately possess: the naked human eye. For this reason, drawdowns to ensure quality have been a staple of ink manufacturers and in-house ink departments for years, but repeatability has been a struggle for just as long. The keys to achieving the highest quality ink are three-fold: density, LAB and Delta E (ΔE or dE) standards. We all understand density, but what are the other two and why do they matter to drawdowns?
Delta E is a metric for understanding how the human eye perceives color difference. It is the measure of change in visual perception of two given colors. The term delta comes from mathematics, meaning change in a variable or function. The suffix E references the German word empfindung, which loosely translates to sensation.
Defining LAB is a little harder. It is similar to geographic coordinates –
The photo below provides us with a visual model of the way Delta E and LAB intertwine:
So how do we apply this information to the press room? First, ink technicians need to have an anilox roller that correlates with the press configuration. A ceramic anilox roller, with or without doctor blades. Secondly: records, records, records! These are the most important factor in repeatability (hint: lab notebooks). To properly correlate ink to press with the knowledge you collect involves gathering the necessary samples and following these seven steps:
As technology has increased, so has our ability to manage and measure ink properly. Printers expect that the variables keeping them from increasing press-side productivity will be eliminated by technology advancements. Pamarco has been gathering ink proofing data for over ten years with the goal of reducing on-press ink adjustments in an effort to meet those expectations. Iris is a great tool do just that – in a repeatable, consistent, automated manner. It helps reduce ink consumption and its associated cost, shortens press setup and reduces color approval issues, and ensures that you get the color you need every time. Iris also works with current Pamarco hand proofers, so your old equipment isn’t becoming obsolete but updated instead.
This is all possible because Iris provides a tool that allows the ink department to improve accuracy and speed while increasing press productivity by removing ink adjustment from the press room. With variable speed settings that equate to idle at 1 foot per min to 300 FPM, the operator saves time. And with the ability to use doctor blade systems, there is enhanced calibration with production conditions. The value of ink proofing and this proofer device are readily applicable to the coating industry and specialty coatings systems as well as proofing for gravure. The options are limitless.
So we’ve walked through the importance of ink proofing and how Iris is a great tool – what now? You’ve started to run your production job. What’s critical? Being able to maintain the color that is in the bucket and being applied to the web or sheet, right? It needs to deliver the same ink qualities through the first fifteen minutes that it does for the entire twenty-four hour press run – in the middle of winter or the hottest part of summer in the Texas panhandle. Excessive variation in density not only affects color but also increases ink consumption. Running a higher density than what is required to produce the job means that you may be consuming 3-5% more ink than necessary. With ink typically being the second highest raw material cost to produce the job (after substrate cost), savings here can create real value.
At this point, there are two to three areas that need to be at the forefront of your attention: viscosity, pH and temperature – depending on whether your ink is water-based or solvent-based. By managing these three components, color can be maintained throughout the run to minimize waste and increase productivity with fewer defects. If you’d like to know more about how to gain or maintain control in these three areas, please take some time to look over the information we recently published on the subject.
As a company that has been heavily engaged in the management and technology advancement of systems that control ink from the time it is proofed through the end of the run for many years now, Pamarco has gathered a wealth of information that can benefit your company. From technology developments like Iris to viscosity/pH/temperature control systems, and the knowledge that comes with experience, we have the tools you need to get more consistent color than ever before. Contact your representative today to find out what working with Pamarco can do for your print.
About the Author
John Rastetter, as the vice president of sales and marketing for Pamarco’s Flexo division, is responsible for leading the Americas sales team and executing the strategies for sales in North America, Canada, Central, South and Latin America. With more than 30 years in the printing and packaging industries prior to joining Pamarco, John has held various executive positions at some of the leading suppliers to the printing industry, developing and managing sales and service organizations in North America, Asia Pacific and Europe.
Jeff Ashburn is a 30-year veteran of the printing ink industry with a primary focus on paper and board packaging. Jeff currently serves as VP – Corrugated & Merchandise Bag Division for Flint Group Packaging Inks – North America. Throughout his career, Jeff has fulfilled a variety of roles in the commercial and technical facets of the ink industry.If you’d like to know more about how to gain or maintain control over viscosity, pH and temperature, look over the Total Flexographic Ink Management white paper.