On the relations between color, gloss, and surface texture in injection‐molded plastics

Abstract

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.

Evaluating contrast gloss of textured polymeric surfaces

“…From a strict physical perspective, it is then expected that the specimens should exhibit an identical gloss. However, in a previous study by the authors [22], it was indicated that there was a significant contribution from bulk scattering to the measured specular gloss for these specimens resulting in a higher measured gloss in case of the lighter specimens. Figure 5 shows the measured gloss, obtained with a conventional glossmeter, of the five ABS specimens as a function of the CIELAB lightness coordinate L * and clearly a higher lightness corresponded to a higher measured gloss.…”

Injection Molding and Appearance of Cellulose‐Reinforced Composites

“…[35] although this had no effect on the measured gloss, Table 3, probably because the gloss of the composite surfaces was very low. In the case of textured polymeric surfaces, Ignell et al [21] reported that a darker object exhibited a somewhat lower gloss than a lighter object. This effect may contribute to the slightly lower gloss of CF230, but the difference between the gloss values is very small.…”

“…Using a cellulose-reinforced polymeric material, possible enhanced changes in color and surface texture can be related to the limited thermal stability of cellulose. Ignell et al [21] also studied the effect of the injection molding process on the color, gloss and texture of polymeric components and they noted, for example, that a rougher surface appears lighter, even though the composition of the material has not changed. This is related to increased proportion of light diffusely reflected from the surface.…”

Factors Affecting Gloss and Color of Decorative Pressure Sensitive Adhesive Films During Thermomechanical Deformation

“…Little research exists in the area of surface appearance for manufactured polymer products. Color and gloss and their relationship to surface topography have been studied by a few authors for the injection molding of plastics and for blown film extrusion , though most other polymer forming technologies have been all but ignored. Gloss is the influencing factor affecting our visual perception of an object when reflected light is largely in the specular direction whereas color dominates our interpretation of surface appearance when the reflected light is diffused in all directions.…”

“…Gloss is the influencing factor affecting our visual perception of an object when reflected light is largely in the specular direction whereas color dominates our interpretation of surface appearance when the reflected light is diffused in all directions. These two factors of color and gloss are generally not independent, for example it is common to perceive the color of a surface being less intense for matte finishes compared to glossy ones ; clear coatings have similarly been noted to reduce the color intensity of underlying surfaces . Surface topography affects both color and gloss and can be referring to purposefully applied surface textures, macroscopic defects like sink marks and weld lines, or microscopic defects like microcracking, poor pigment and filler dispersion , or crystalline rearrangement .…”