Instrumental Evaluations
Instrumental Evaluations
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Instrumental evaluations, like visual evaluations, must be accurate, precise and reproducible. The reproducibility issue with instrumental evaluations can be a hidden problem. When generating numerical and/or graphical data for colored samples, reproducible data becomes a statistical issue. Often, users will measure a sample once, then use that numerical reading as an absolute and indisputable reference. Such practices are risky, and observers should perform statistical Gage Repeatability and Reproducibility studies (GR&Rs) to determine the number of measurements that must be averaged to generate acceptable data. ColorXpress* Services has conducted Six Sigma GR&Rs which have indicated that a minimum of 2 measurements (ideally with 90° rotation) should be averaged for acceptable measurement system variation. Most of the objectives of a numerical instrumental assessment are similar to those of a visual assessment. All must be satisfied to generate valid data. This is the reason that ColorXpress* Services asks for the measurement criteria on our Color Match Request form. The Instrument and Data Evaluations:
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