An Experiment in Visual Scaling of Small Color Differences*

Under the auspices of the ISCC Committee on Color Difference Problems, an experiment was carried out in the visual scaling of small color differences involving six color microspaces. The object‐color samples were visually evaluated by ranking, by subjective estimation, and by acceptability judgments. Visual scales were calculated by traditional procedures. Correlations were calculated between the visual scales and four color‐difference formulas (CIELAB, C1ELUV, FMC‐2, and FCM), and ellipsoids were optimized to the visual data. No fundamental differences were found between the results of the perceptibility judgments and the acceptability judgments. Higher correlations than reported for earlier comparable experiments were obtained between visual and calculated color differences.