Abstract: The invention provides a substantially flat film or metallized film, reinforced with regularly spaced reinforcing yarns in the fill and warp direction having a residual shrinkage of less than about 2.0%, which is dimensionally stable over a wide range of temperatures, along with a process for producing the same. Synthetic reinforcing yarns, including nylon yarns, can be preshrunk by heating the spooled yarn in an inert atmosphere for a sufficient period of time to reduce the residual shrinkage in the spooled yarn to less than about 2.0%. This preshrunk yarn can then be bonded to a film or metallized film substrate using a wide variety of adhesives, including hot melt adhesives, or water-based adhesives cured by application of heat. Because the residual shrinkage in the reinforcing fibers has been reduced, subsequent application of heat during manufacturing processes, or in the use environment, will not produce the curling or puckering of the film or separation of the metal layer.