Getting Printing Right – QUICKLY!
By Bill Knotts, Spartanics
As the theme of this issue—Printing and Personalization—suggests, there are a range of new printing techniques that should be considered by any ICMA card manufacturer member with an eye on remaining competitive. Some new loyalty card products, for example, require a perfecting of process color printing not previously needed in many other high value card applications. What is becoming apparent to those of us who work with a wide swath of companies in the industry, is that the most competitive card manufacturers are often the ones that are equipped to incorporate upgrades in production procedures relatively quickly. To an increasing extent, significant reductions in the time and money spent on empirical testing of new printing methods, or any changes in production techniques for that matter, can be traced to the relative sophistication of quality control technology on hand to monitor such changes in processes.
Consider, for example, what it takes to simply switch the types of inks used in your printing presses. There are indeed many card manufacturers who are taking a closer look at the more environmentally-friendly, water-based inks. The heating and squeezing inherent in lamination processes inevitably means that the color you print is not the color of the ultimate laminated product. Rather, one must purposely print what is an unacceptable color when immediately post-press in hopes that it will shift into the acceptable range upon lamination, because of lamination’s effect of increasing color saturation and giving the appearance of richer colors.
Most card manufacturers have been down this road before and know that when you change inks, you must then use successive iterations of initial post-press colors to find the right pre-lamination hues that created the ultimately desired color match in the final product. When you are simply matching logo colors, this is relatively doable, if time consuming. In such cases, you simply do empirical tests to find the right mix of pigments that will match the original color.
It is a far more difficult proposition, however, to do such empirical testing when it comes to products made with process color techniques. The nature of process color printing is such that colors will appear differently depending on where they are at in the color space. In CYMK color systems, for example, yellow inks are relatively unstable, usually shifting more in lamination processes than other pigments. This can turn into a big headache as you try to add more yellow, but then find your greens becoming unacceptable. Unlike corrections made with solid colors, process color corrections are not linear. Yellow pigments might be fully corrected at 30% coverage, but then become unacceptable at 50% coverage. You can get the right pre-lamination color mix; BUT, it takes many more iterations to get there. The speedier you can do these color matching assessments, and the more data you can bring to bear on your color matching exercises, the sooner you will be able to make the ink changes you desire.
Card manufacturers using latest generation automated inspection technology have a clear leg up over those without automated capabilities to monitor defects in large numbers of cards quickly. In this example of ink switches in process color applications, attempts to use more primitive color matching technology fall short for several reasons. First, the considerable speed of automated inspection systems, i.e. full inspection of 10 cards/second, means that you are getting considerable data on color characteristics at a pace well beyond what less fully-automated colorimeters (and human inspectors!) can achieve.
Moreover, the better fully-automated card inspection systems look at every inch of both sides of a card, in contrast to more primitive colorimeter technology that instead limit inspection to a finite number of regions of interest. Second, because best-of-the-line automated inspection systems use automatic pattern alignment that can count color matches pixel by pixel, if necessary—without the need for human inspectors to align images—they are far more accurate tools that give more reliable data for color matching.
Human error and the inevitable inconsistencies they entail create time drains when image alignment is done manually.
Third, the best automated inspection systems use color matching standards (CIELAB) that measure color matches mathematically to a traceable standard and that take into account how human perception varies across color ranges. CIELAB color verification is especially useful because it defines color matches that are perceptually uniform.
Lastly, automated inspection systems process data instantaneously and give you minute-to-minute feedback on your color corrections. These systems will record, graph and report on trends in color; or for that matter, any parameter you are monitoring. For example, they can set a minimum, maximum and mean value for color matches and, over the course of one minute intervals of inspection time, indicate if color is holding or drifting away—such that corrections can be made before processes get out of bounds and beyond your pre-defined “ideal.”
As this consideration of simply switching inks suggests, no change in printing techniques is without headaches. However, if the inevitable difficulties in changing production processes have kept you from experimenting with improved printing techniques that are tied to new market opportunities, you may be losing ground to competitors. Using automated inspection technology as a tool to help transition to any new process should be considered as a way to get to where you want to go relatively quickly.