Details:
Summary:
The introduction of portable, battery powered spectrophotometers in the late 1980s has made precision color measurement available on a wide scale. Although individual instruments may display high precision, for a given set of data, users often find substantial lack of agreement between measurements made on different days, or, when comparing data collected from different instruments. This lack of agreement adversely affects productivity and the quality of decisions that are based on the data. We tested the color measurement capability of instruments from four manufacturers consisting of 45? and diffuse geometries. Test materials consisted of Munsell color chips, matte and glossy, and BCRA Tiles. The two instruments designed from graphic arts applications had generally high levels of precision, while the two general purpose instruments had somewhat lower precision. Measurable differences do exist between units of the same type from the same vendor. Agreement between instruments of the same type from different vendors may not be adequate for critical applications. The two instruments designed from graphic arts applications had generally high levels of precision, while the two general purpose instruments had somewhat lower precision. Measurable differences do exist between units of the same type from the same vendor. Agreement between instruments of the same type from different vendors may not be adequate for critical applications. We also examined the plaques used to calibrate and check the test instruments. In some cases, these plaques contribute a needlessly large portion of the within- and between-instrument error.