Characterization and enhancement of a mobile local scattering environment. At least one arm rest assembly is carried by the seat frame and including an arm rest mounted for pivotal movement about a pivot member between a use position with an upper support surface in a horizontal position for supporting a forearm of a passenger seated in the seat, and a stowed position wherein the upper support surface of the arm rest is perpendicular to the use position. Further, this technique may be used to enhance color toner Glossmark images across the low and high density areas of application where the differential gloss effect would otherwise be weak. Furthermore, an overhead line configuration has such a specified holding device.