Step Size and Uniformity of Six Color Atlases by Adjacent Pair Comparisons

ABSTRACT Color systems and atlases are critical tools for defining, organizing, and communicating colors across industrial, scientific, and artistic domains. While widely adopted systems—including Munsell, Natural Color System (NCS), DIN, Coloro, Pantone Fashion, Home + Interiors numbering system (Pantone FHI), and Sino Color Book (SCB)—leverage distinct organizational principles and application‐specific advantages, their step sizes (spacing between adjacent chips) and uniformity (consistency of spacing) have not been compared. This study evaluates these metrics using four color difference formulas (CIELAB, CMC, CIEDE2000, and CAM16‐UCS) to quantify step sizes and the coefficient of variation (CV) to assess uniformity. In terms of step size, key findings reveal that Coloro achieves the smallest median step size (with CIELAB values of 2.2, 1.6, and 1.8 in the Hue, Lightness, and Chroma attributes, respectively), but contains only a limited number of adjacent pairs. SCB ranks second (with CIELAB values of 2.0, 3.0, and 2.2 in the Hue, Depth, and Chroma attributes, respectively), yet it comprises a substantially larger number of pairs. In terms of uniformity, SCB exhibits superior uniformity in the Hue attribute. Both Munsell and DIN excel in uniformity in the Value/Darkness attribute. NCS leads in uniformity for the Chroma attribute. Crucially, no single system and atlas optimize across all attributes. These findings clarify system‐specific strengths and highlight the challenge of integrating these strengths into a unified color system, while providing a foundation for future research in color order systems.