In order to determine the visual perceptibility of surface defects of high quality parts a novel measurement methodology was developed. It displays results which are remarkably close to the human perception and enables fast non-subjective IN-LINE differentiation between different visual surface qualities. In further consequence it enables a better in-depth optimization of injection molding and extrusion processes. Various properties of the human visual perception process were incorporated into the development of the mathematical measurement models of this artificial eye, thereby supporting a defect analysis whose results conform to human judgments. Nonetheless, these results are obtained unambiguously and can be reproduced apart from subjective influences. Besides sink marks, numerous other kinds of surface defects can be characterized. Among them are weld lines, moisture streaks, tiger stripes and inhomogeneous gloss. Full areal acquisition and analysis of surfaces compared to linear scanning of other measurement methodologies is used. High precision measurement of high gloss surfaces, in-depth consideration of molds, parts and resulting visual effects and a high processing speed for IN-LINE and IN-SITU applications are further advantages of the newly developed surface inspection method. In order test the new method and also to examine the influence of dynamic mold surface temperature control on perceptual surface properties like weld line strength, as well as gloss, a new test mold, using two different dynamic mold temperature technologies, was used to manufacture bi-directional filled tensile bars from ABS-PC. In particular, the gloss behavior of the surface in dependence on the flow path was examined in the study.