In the packaging world, establishing the customer's or brand owner's expectations is the first step to matching color. "Some use a tight tolerance and some are very loose about it," Wallace explains, "but instrumentation can't tell you how to feel about a color. That can only be done by asking the customer to assess the printed matter inside a light box to determine which samples are pleasing and which are not." Once the samples have been winnowed down, instruments are employed to document the L*a*b value of the sample against the L*a*b of the reference to determine the deviation of the color from the standard (delta E).
Don't forget maintenance
But, how do we know that the selected measurement device can achieve the desired level of accuracy? Regular calibration is key, Wallace says. X-Rite offers the NetProfiler system that enables users to automatically test, measure, and profile their instruments over the Internet. Using sophisticated software and certified physical standards, the system reportedly takes just minutes to produce performance statistics on every instrument within a network. As an alternative, he adds, customers can have their instruments re-certified annually through on-site services provided by companies such as X-Rite. Best practices for the optimum use of measuring devices call for measurement conditions to be set to standards regarding luminescence, measurement angle, and substrate and other parameters.
Wallace considers measurement techniques in printing and packaging "pretty well standardized" by now, and said he expects the future will bring the development of more integrated, open-loop scanning systems. pP
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