Details:
Summary:
The use of spectrophotometers to evaluate and monitor ink strength and print quality is rapidly growing. Although instrument manufacturers have established specifications for inter-instrument agreement in a controlled environment, minimal data exists on inter-instrument correlation at multiple sites. In an effort to evaluate multi-site differences, printed test targets were measured at a primary site with a portable 0/45 degree spectrophotometer and then sent to numerous locations for measurements with similar instruments. Statistical evaluation of multi-site differences indicate that significant differences in colorimetric measurements can exist between identical instrumentation. Suspected sources of measurement error (calibration, temperature/humidity, inter-instrument repeatability, fade, individual user repeatability and multiple user repeatability) were studied and ranked. The importance of taking inter-instrument variations into consideration when establishing color tolerances for multiple instruments is also discussed.