The effect of an imposed texture on the gloss of injection‐molded polymeric surfaces was evaluated as well as the way in which these properties are visually perceived. Specimens having small differences in surface topography were produced using two mold cavities with slight differences in texture and three different polymers. The texture and gloss were characterized using laser profilometry, gloss measurements, and by means of psychometric evaluations. The measured surface topography parameters and gloss were determined mainly by the texture of the mold surface and the gloss also by the processing conditions. Variations in surface topography due to differences in the rheological properties of the polymer melts were, in most cases, too small to be reflected in the measurements. The visual assessments of the texture and the gloss of specimens from the same cavity were in fair agreement with the measurements, although the observers could discern differences between some specimens not revealed by the measurements. When the specimens molded in the two cavities differing significantly both in gloss and texture were compared, the agreement between the measured topography parameters and the perceived roughness was poorer. It is suggested that higher gloss of a textured surface enhances the perception of a higher roughness. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers

The concept of contrast gloss and its relation to visually perceived gloss was examined for textured polymeric specimens. The specimens were injection‐molded plaques manufactured in three different polymers (acrylonitrile‐butadiene‐styrene copolymer, polypropylene, and a blend of polycarbonate and acrylonitrile‐butadiene‐styrene copolymer). A contrast gloss factor was determined from the reflectance data obtained with a conventional multiangle spectrophotometer. To evaluate the visual impression of gloss of the specimens a psychometric study was performed. The contrast gloss factor corresponded well with the visual assessment of the gloss and it was able to discern the visual differences between several specimens not significantly discriminated by their gloss values. These latter gloss values were obtained with a conventional glossmeter measuring specular gloss. In correspondence with the visual assessments and practical experience, the relation between the contrast gloss factor and the specular glossmeter measurements was found to depend on the type of polymer used. When evaluating gloss of specimens varying in color, the contrast gloss factor corresponded well with the visual assessments. This was in contrast to the specular glossmeter measurements which ranked the specimens essentially in the opposite order. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

The relation between color and gloss of injection-molded plastic specimens was evaluated by means of a 458/08 geometry spectrophotometer and a glossmeter. The specimens were plaques having one smooth, glossy field and one rougher, textured region made of two different polymeric materials (acrylonitrile-butadiene-styrene and polypropylene) in a range of colors. A significant influence of the lightness L* of the specimens on the measured gloss of the textured field, with a low gloss appearance, was found. This can probably be attributed to a contribution from bulk scattering, which is linked to the reflectance from within the specimen. The influence of texture on the measured color of the plaques was assessed by evaluating the color difference between the smooth field and the more textured area on the specimens. When the surface was textured, the color changed; in general it became lighter and less saturated. The magnitude of the change depended on the color of the material. The darker the material was, the larger was the increase in lightness L* as the surface became rougher. The shift in chroma C* was determined not only by the saturation but also by the lightness of the specimens. Darker specimens exhibited a larger decrease in chroma when the surface was textured. The change in the measured color caused by increasing the surface roughness could be predicted in a satisfactory manner using a model developed for xerographic printing paper.