The roles of blend composition and process parameters on the metallic luster of extruded polymer films and spray-coated samples have been investigated. The metallic luster is determined by the orientation of platy metallic particles which is determined from X-ray intensity ratio (XIR) of the (200) and (111) planes of the aluminum crystal lattice. The metallic luster is an optical property that is measured by the flop values derived from light scattering measurements. The XIR and flop are useful for monitoring the effect of changes in blend composition and process parameters. Addition of different shaped particles has a different effect on the orientation of aluminum flakes. It is shown that aluminum platy particles orient only when they are first dispersed in an appropriate dispersing polymer. A methodology is developed for matching the metallic luster of both spray-coated and extruded polymer resin formulations by coupling XIR data with the flop values. This methodology is shown to be useful for optimizing the process conditions and composition of polymeric blends containing aluminum flakes needed to achieve the required metallic appearance in polymer films and articles. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012