What is Closed-Loop Color Process Control for Offset, Flexo & Digital Presses and Why it’s Time to Retrofit
Periodic color monitoring and control of aim characteristics (color, density, TVI, G7, etc.) of an offset, flexo,or digital press is extremely important for ensuring accurate and consistent color reproduction throughout the press run. These operations can either be accomplished manually, semi-automatically or automatically via color measurement hardware and color control software.
Manual color control is a primitive method of quality control that uses a “trial and error” process—and it’s costing printers worldwide millions of dollars in wasted material, lost productivity and profits, and lost revenue from poor quality products being rejected and leading to customers switching to print vendors who have transformed their quality processes with automation. Trailing edge printers typically lean on a seasoned press operator’s tribal knowledge of how to take corrective action to “get on color”. But this craft is disappearing, as these experienced press operators are retiring from the printing industry at unprecedented rates. When this happens to a printer who hasn’t modernized their color control and management in advance, they’re forced to leave the manual process in the hands of less experienced operators. This results in even longer make ready times, more waste, higher risk of customer dissatisfaction, and lower profits. Regardless of the print technology, the manual process involves:
- Interrupting press operations
- Pulling sample sheets
- Performing manual measurements of printed color bars
- Making estimations of color density correction values by eye
- Tweaking press controls by hand to implement changes
- Running the press again until the adjustments take hold
- Stopping the press, pulling additional samples, and measuring & checking again if corrective actions were successful
- Repeating these steps until the press is (hopefully) up to color
This sequence of monitoring and correction occurs during both the “make-ready” and “production” phases of a press run. And because this process is so labor intensive and time consuming, many times press operators feel the need to skip on these important color validation steps.
