Investigation of the Effect of Structure Spectrum on the Appearance of Automotive Finishes

Assessment of the total appearance of an automotive coating using standard methods would have a great impact in the automotive industry. These methods should have a good correlation with visual assessments. In this research, the correlation between visual assessments and the wave scan DOI results were investigated for white, metallic grey and metallic black automotive samples. The visual assessments were carried out by a panel of 14 observers, including 6 males and 8 females under a light source simulating D65 in a light cabinet with a viewing geometry of 45/0. The visual assessment method used was one of paired comparison. Such quality rankings were then converted to quantitative equivalents by the aid of the Thurston scale and the results were compared with each of the wave scan output parameters. Statistical and error estimation parameters (i.e. R 2 and stress) illustrated that amongst all wave scan parameters, only Wd, Wc, LW and in that order strongly correlated with human evaluations of geometric attributes for these achromatic paint samples. Investigation of structure spectrum showed that Wb is another important parameter indirectly influencing on the surface appearance and in fact the value of Wb is greater than Wd and Wc in the acceptable region. Therefore, there seems to be a complex relationship between these parameters which represent the short and the long waves which is of utmost importance in assessing perceived total appearance. J. Color Sci. Tech. 7(2013), 123-131©. Institute for Color Science and Technology