Perceived speed of changing color in chroma and hue directions in CIELAB

In dynamic LED lighting, the perceived speed of changing color is an important concept; however, there exists no suitable temporal color space. In a psychophysical experiment, we compared the perceived speed of periodic temporal transitions in CIELAB chroma and hue directions around five base colors [the five Munsell hues: 5R (red), 5Y (yellow), 5G (green), 5B (blue), and 5P (purple)]. The experiment was conducted in a light laboratory, with the main illumination stimulus subtending a visual angle of 101 × 77 deg. In sequential paired presentations, observers were asked to identify which transition appeared faster, and points of subjective equality between transitions were computed. The speed of transitions was defined in CIELAB ΔE ab∕s, which was shown to be temporally non-uniform; uniformity was improved using a modified color space based on speeds in the DKL space of Derrington et al.