The billboard customers of Cooley Group noticed that printed image quality, dry-time, and ink adhesion are proportionally better with increasing vinyl thickness on the surface of our reinforced wide-format media.To best serve our customers, and to position ourselves better in the marketplace, we undertook a study to determine the underlying cause of the quality difference and to identify whether the surface is smoother or the chemistry on the surface changes.Our investigation relied heavily on quantitative image quality measurements and chemical analysis of the surfaces of prints made on various substrates with differing vinyl thickness.This paper will detail our process in identifying the root cause of this change in image quality. Technical data will be presented and analyzed.