Investigating Colorimetric Specifications of Metallic Paints in Automotive Industry Based on CIE System

Body appearance and color is the first feature, which is considered by the customer. The bodies of vehicles are painted in different methods in order to have the best appearance as well as corrosion and other abusing effects resistance. Pigment is responsible for rendering different hues. The pigments are crystalline semi powder particles, which are distributed in paint film layer in order to an optimum hue attained. The physical mechanism of hue is dependent on two factors: light absorption and distribution. When using fine glossy particles, the quality of the product is different from the conventional one and is called metallic or pearlescent. These particles made of fine flakes of aluminum, mica or a mixture of them. Metallic paints are the most economical, easy-application coating systems. These paints have three-color evaluation parameters: Lightness, saturation, hue. In order to investigate the mentioned expressions, a comparison between solid, transparent and metallic was carried out and their optical properties were determined according to CIE (1976) standard. One important issue in this investigation was to evaluate the effect of nonleafing aluminum flake pigments on optical properties including lightness (L *), saturation (C *) and hue (H *) and to prepare spectral reflectance curves for metallic coating in comparison with solid and transparent ones.

Keywords:

Solid paint , Transparent paint , Metallic paint , Pigment , Leafing and nonleafing aluminum flakes , Cie system , Lightness , Saturation , Hue