A Comparison of Color Measured with Three Optical Geometries, Part II, BCRA Color Tiles

Color measurements of twelve British Ceramic Research Association (BCRA) standard color tiles were made with a variety of spectrophotometers. The instruments chosen were both bench and portable types having 0/45, 45/0, and D/8 (integrating sphere) geometries. Significant differences were observed between 0/45 and 45/0 geometries despite the presumed interchangeability of these two optical systems. As expected, D/8 integrating sphere geometry differed considerably, and to the same degree, from the other two. Agreement between spectrophotometers having the same optical geometry and made by the same manufacturer was generally good. A comparison of these results with those made previously1 (TAGA 93) using the same spectrophotometers with printed color samples showed somewhat decreased color differences with BCRA tiles. A comparison of these results with those made previously1 (TAGA 93) using the same spectrophotometers with printed color samples showed somewhat decreased color differences with BCRA tiles. This study reinforces the conclusion that when colorimetric data are to be compared, it is essential that spectrophotometers having the same geometry be used. If they are not, it is important to know the magnitude of the differences that do exist.