A method for coating a thin film of a non-polymeric compound on a substrate by providing a mixture of the non-polymeric compound and a fluid carrier. This mixture is then pumped into the interior of a heated evaporation box having an internal temperature sufficient to convert substantially all of the non-polymeric compound and fluid carrier to a gaseous form. The non-polymeric compound and fluid carrier are then removed from the evaporation box via exit slit in the evaporation box. Adjacent to the exit slit, and maintained in a vacuum, is a substrate upon which the non-polymeric compound condenses. The substrate is in motion, for example on a web roller, thereby allowing a continuous coating of the non-polymeric compound to be applied to the substrate.