Method for classifying and arranging metallic paint colors

A process to determine a representative color of a metallic paint color, which comprises:

• calculating a representative angle (D) of a metallic paint color by Equation (1):
• D=a1×V1+a2×V2+b (1)
• wherein V1 and V2 are definition values which have been calculated from colorimetric values of the metallic paint color on a highlighted side and a shaded side, respectively, and wherein a1, a2 and b are multiple regression coefficients which have been determined from a plurality of metallic paint colors, said multiple regression coefficients a1, a2 and b being calculated by means of multiple regression analysis of the plurality of metallic paint colors with use of representative angle, as object variable, of each of the paint colors obtained by visual observation and with use of V1 and V2, as explanatory variables, of each of the paint colors, and said definition value V being an amount which is calculated from lightness L* and chroma c* by the following Equation (2):
• V=sqrt(L*{circumflex over ( )}2+c*{circumflex over ( )}2) (2);
• determining a spectral reflectance of the metallic paint color at the calculated representative angle (D), and
• determining a Lab* value from the determined spectral reflectance, to determine the representative color of the metallic paint color.