Rationale

ASTM D4265 Utilizes CIELAB L*a*b* color space to calculate dE* (total color difference) as a part of its SRI and RSI calculations. Color science continues to evolve as we learn more about the human perception and the human eye. The color industry also has several other color difference equations (DECMC / DE2000) that is recommends, especially to correlate better to human perception. It is my recommendation to include these as options in the calculations for SRI and RSI if a company so chooses. ASTM E2244 - Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates. Method states: 5.2 Color differences calculated in ?ECMC or ?E00 units are highly recommended for use with color-differences in the range of 0.0 to 5.0 ?E*ab units. Both are appropriate for and widely used in industrial and commercial applications including, but not limited to, automobiles, coatings, cosmetics, inks, packaging, paints, plastics, printing, security, and textiles.