How Ink and Press Correlation Can Increase Your Bottom Line
After twenty-two years in the printing and packaging industry, I have learned that the key to successful printing is being proactive in every step of the process. Every hour spent with a downed press carries a high price tag for any printer. Whether that downtime is from failing to coordinate your ink in the lab with the tools on the floor or it’s from stopping to deep clean a piece of machinery, the implications of the press not running are important to recognize and avoid. Optimizing the uptime of your printing press, and increasing your bottom line by doing so, means staying ahead of problems rather than chasing them.
We’ll tackle maintenance first because this is one of those never ending conversations on the printing floor. On both the press side and within the lab, anilox roller maintenance and cleaning are a necessity. A dirty roll can make as much as a thirty percent difference in ink drawdowns. It’s absolutely critical to implement preventative care measures: consistency in cleaning in the lab and on the press floor are, to this day, some of the biggest hurdles that printers need to overcome in order to be successful in producing quality print. Most of it is common sense and procedure, but it must be done.
Delta E, on the other hand, presents a different challenge altogether because there are so many variables to settle between the printer and the end user. Everyone has to be on the same page – the customer, the printer and the suppliers. The different components within the realm of delta E that have to be aligned are what delta E standard to use, the light standards, the allowable tolerances, and the observer light angle.
Over the years, delta E standards have been revamped repeatedly; meaning that the actual equation for it has changed so you need to be sure that everyone is using the same equation. The allowable tolerances run a similar gamut: everyone needs to agree on what the tolerances actually are and take steps to hold to them. The parameters set by allowable tolerances are a go versus no-go for customer color acceptance.
Two main lighting measuring components have a big impact on the final color as well. When it comes to light sources, a spectrophotometer is used to measure color using different light standards – cool white fluorescents, incandescent light bulbs, daylight, etc. The customer needs to agree with the light source being used because it will change the outcome of the color being printed. And finally, the other variable measuring component is the light angle. It can be either a 2° observer or a 10° observer. Again, everyone needs to be on the same page so that the final color does not vary.
Once maintenance and the delta E variables are managed, the next step is to look at what it means to correlate ink to press in general terms – we’ll get to individualization last. When thinking of the steps involved in this process, it’s helpful to keep in mind that the goal is having your ink matched to the extent that it will produce to a very near standard on any press, in any environment. This eliminates future press downtime for ink matching because all trial and error is performed in the lab to use for subsequent batches, limiting the possibilities for a thousand dollar an hour price tag.
As a quick refresh (or for anyone new to it), the general process for correlating should follow this outline: a customer-approved color standard is created on press. The ink is then taken to the color lab in its wet form (same as the one used for approval), where the lab applies the same parameters as those used on the press floor and creates a drawdown to match the printed sample. The lab then continues to use various proofer anilox rollers to hone in on a near perfect match. During this laboratory process, documentation is key: it provides the correction ratio of anilox roll from lab to press. In other words, the lab is documenting and measuring the delta E value both in the color lab and with what’s being used on press until a 1-to-1 volume match is found. Once that target is hit and the data on how it was done is collected, that correction ratio allows you to produce it anywhere to an incredibly near standard.
Now, obviously this process is going to have individualization factors. We often refer to these as critical variables. These are the factors that can be affected by two major elements: the environment and your suppliers. If the variables of the printing plate and substrate vary greatly, you’ll constantly be trying to hit a moving target. Because of this, I always recommend getting suppliers involved.
By engaging your suppliers in the conversation about stabilizing variables, you’ll find yourself with consistent pH and viscosity in ink, paper with tight tolerances, and photopolymer plates with equivalent durometers – just to list a few examples. Imagine if each one of these components was different from batch to batch: the degree to which that could affect your print quality and color matching accuracy is staggering. Optimizing batch consistency means stabilizing everything involved in ink correlation, from the lab to the press, so involving your suppliers is a very good practice.
The last step to ensuring that your individual correlation needs are met is bringing in someone with experience to measure how efficiently your press room is currently operating. This is something that I do often and one of the things that I highlight is your level of repeatability and reproducibility. How consistent are you? Are all of your lab technicians performing tasks with the same methods and level of efficiency? Have you performed drawdowns on multiple days to test your variations? Taking this type of approach will pay off in the end when your print quality increases and your bottom line does, too.
In the end, it always goes back to keeping ahead of the curve ball instead of trying to catch up to it: being proactive in your process. We all know that the key to a healthy return on investment is keeping your presses running efficiently and consistently minimizing downtime. You’ll be able to do just that by bringing in suppliers and experts to help you properly correlate your lab to press and show you ways to better adhere to recommended maintenance practices. Simply following these steps will ensure a better outcome for your business in the long run – you’ll thank yourself later.
Author :Rick Spong
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