Are technological advancements in machinery allowing brand customers to expect higher-quality printing? Are brands simply pushing printers for higher quality, which is then driving the development of new technology?
To a degree, both can be answered with a resounding, “Yes!” Why? High-tech equipment, coupled with continual calls for improvement, are causing an absolute print quality transformation in the flexo industry.
The push for higher quality is also being coupled with another important and more devastating trend for printers: Brands are moving toward an increased number of SKUs, shorter printrun lengths and tighter color tolerances. This shifting landscape creates unfavorable conditions for printers who must perform additional makereadies to accommodate the shorter pressruns.
All photos courtesy of Techkon USA
In addition, makeready times are unfortunately getting even longer, so that printers can achieve the new tighter color tolerances being placed on them. Together, more makereadies and longer makereadies translate to much lower profit margins for flexography and package printers.
So, what can printers do in this situation to maintain profitability and still meet customers’ expectations? Here are two strategies I see printers employing to address the challenges imposed by brand owners: Print to the numbers, and invest in an inline spectrophotometer for automated color measurements.
Both of these solutions allow printers to:
- Take control of the color print process
- Remove the color guesswork
- Deploy a more repeatable manufacturing process
- Reduce makeready times
- Achieve higher overall color quality and consistent, repeatable results
Print to the Numbers!
So, just what “numbers” are we talking about here? This depends entirely on the type of work you are printing. For those printing spot colors, like Pantone or brand colors, running to the numbers means using a spectrophotometer to measure CIE Lab values of those spot inks and adhering to the Delta E tolerances agreed upon with the customer.
Taking color measurements to determine the accuracy of spot colors is far more predictable than making visual assessments and guessing at corrections on press. With a single measurement, many spectrophotometers and pressroom color management software solutions can instantly guide press operators to the lowest possible Delta E by providing very specific density adjustments. In some cases, the software will also immediately indicate to the operator if a fundamental problem exists with an ink, specifying to either “tone” it on press or reformulate it back in the ink department. Put succinctly, allow math and science to quickly call the shots and replace the subjective judgment of your press operators, where experience levels can vary drastically. The name of the game here is reducing the guesswork and turning your color print process into one that is predictable and repeatable.
In the case of process CMYK or expanded gamut (EG) work, there are good reasons to adopt one of the many industry-standard print conditions available today. These include:
- FTA’s Flexographic Image Reproduction Specifications & Tolerances (FIRST)
- ISO 12647-6
- GRACoL 2013 (CRPC6)
Given the demands on flexo printers for shorter run lengths and tighter color tolerances, adoption of an industry color standard and running to the numbers is extremely beneficial. It provides a known print condition with quantifiable color metrics that can be measured and controlled (density, CIE Lab, TVI, hue angle, etc.) to remove the guesswork and ensure you have a known, stable and predictable color process you can achieve day in and day out.
While using a spectrophotometer as a guide to find and achieve your color standards faster is a timesaver in makeready, taking periodic color measurements throughout production is also important to ensure you maintain color consistency throughout the job. This production check will prevent costly remakes. Perhaps that’s why many brand customers now require measurements throughout production to ensure compliance with job tolerances.
Why Measure Inline?
While the benefits are clear for adopting an industry color standard and printing to the numbers, let’s now look at the benefits associated with inline color measurement systems and how they can further help printers reduce makeready times and ensure conformance with the print standard.
Don’t misunderstand me: It is a huge step in the right direction for a printer to just adopt an industry standard and print to the numbers using a handheld spectrophotometer to stay on course and achieve the tolerances. However, the benefits of inline color measurement take this to a whole different level and do much more to increase profitability.
We see it all the time with flexo printers who have made the leap and are printing to the numbers using a handheld spectrophotometer. While color measurements serve as a guide to get press operators up to color during makeready, the press must still be stopped repeatedly so samples can be cut from the web and measured offline—a time-consuming process. As a result, once in production, typically, color measurements are only made at the end of a roll. Oftentimes, this proves too late if color has drifted out of tolerance. It’s an expensive problem if the roll is rejected and must be re-printed.
Now, consider the same process with an inline spectrophotometer. During makeready:
- Color measurements can be made while the press is moving
- Results are displayed back to the operator instantaneously
- There is no need to ever stop the press to check color
- Press-side color management software is providing real-time color adjustment recommendations to the operator, meaning they can close the loop and achieve their color standards as quickly as possible
Real-time color adjustment recommendations are helpful to even the most seasoned press operators and an absolute lifeline for the younger and less experienced operators that are running many flexo presses today. By avoiding the starts and stops during makeready, inline color measurement systems can easily cut makeready times in half and greatly reduce wasted materials, resulting in higher profit margins for the printer.
Once out of makeready and into production, even though color does not tend to shift very quickly on a flexo press, inline measurement systems continue to play an indispensable role through continuous monitoring and alerting press operators when a shift is detected. In this way, inline systems are somewhat “predictive” and act as an early warning system to allow press operators to intervene and make the necessary corrections before colors go out of tolerance. The net effect is far more consistent color and happier brand clients.
Contrast this to the more common scenario, where a press operator only checks color at the end of a roll, and then occasionally has to trash the roll if the color is found to be out of tolerance. Again, here is where the benefits of an inline color measurement system are obvious and the ROI starts to make excellent business sense for printers.
Measuring color inline is also a great way to ensure the measurements happen at regular intervals and the data gets collected. As discussed, brand customers are getting serious about holding printers to the standards and tolerances. This becomes risky business for printers if the brand detects color differences throughout a pressrun and across multiple pressruns over time. Measuring inline is easy and it happens automatically, so press operators will have all the information necessary to ensure color compliance. It won’t slow the press down or interfere with normal duties. Also consider that some inline systems retain and store all of the measured color and job information on cloud-based servers, which allows the data to be accessed by quality managers for customer-facing reports, internal audits, continuous learning and internal process improvement efforts.
Eye-Sight
Inline color measurement systems generally consist of the same key components. Most importantly, each will feature a color measurement instrument (preferably a true spectrophotometer, but sometimes an RGB camera). The color measurement head is then coupled with a 2D camera that provides “eye-sight” to the system, allowing it to find color bars and color measurement locations.
Both of these components are then mounted to a traverse arm that allows the system to quickly move across the web and enable it to take color measurements anywhere in the printed impression. Next, the system will include an ISO-compliant backer board, or backer plate, so color measurements are consistent over time and agree with conventional handheld spectrophotometers. Finally, the system will consist of a computer and display(s) that can be mounted near the press and allow the operator to control the system, view measurement feedback and receive recommended color adjustments.
What to Look for
There are four areas to focus on as criteria for selecting a system:
- Measurement Speed: To ensure the maximum benefit from an inline system. Some older systems are only capable of measuring one color patch at a time, which makes them impractical for use during makeready, and rendering them only viable to monitor color once the job goes into production. However, newer inline systems have the capability to measure an entire color bar in a single printed impression, which means they are fast enough for use during makeready. This is probably the biggest benefit for printers who are facing the trend of shorter pressruns and higher color tolerances
- Measurement Technology: The measurement head will likely either be a true spectrophotometer, delivering full spectral data, or an RGB camera that is capable of delivering only CIE Lab values. This is important to keep in mind because the absolute color accuracy can vary on camera-based systems, depending on changes to the ink and substrate combination being used. Spectrophotometers cannot be fooled in this way and will always provide the highest level of color accuracy and the best agreement with handheld spectrophotometers that are used in the ink department, on other presses or by the brand customer
- Price: While inline color measurement systems have been available for many years, their high price tags have severely hindered widespread adoption. Today, newer systems have become available with dramatically lower prices and ROIs that now make sense for presses of all sizes—Even down to narrow web label presses
- Other Key Features: Inline color measurement systems are sometimes positioned as an option or bundled with 100 percent inspection systems, while other times, they are sold as stand-alone units. Some inline color systems also offer expanded capabilities, like live web viewing and ISO/ANSI-style bar code grading. Consider the software interface. Look for something that is easy and intuitive for your press operators. Complicated software can be intimidating and encumber deployment and adoption of this technology. Also, take a look at the reporting capabilities of the solution. Make sure it has the ability to create reports tailored to the needs of brand customers and your internal quality department that may require more specific and detailed information
Final Takes
Both shorter run lengths and tighter color tolerances are putting the squeeze on flexo printers and decreasing their profit margins. To alleviate such pressures, implementation of industry color standards and investment in an inline color measurement system are great success strategies that work well together.
The tandem allows printers to reduce makeready times and trim material waste by automating the color measurement process, removing guesswork, and transforming package printing into a highly reliable and predictable manufacturing process.
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