The feasibility of using a dilute bottom carrier layer to reduce the thickness of a viscous top layer for tensioned-web slot coating was examined experimentally. Aqueous poly(vinyl) alcohol solutions were prepared for both the carrier and the top layers. The solutions were coated on poly(ethylene terephthalate) films for observation. The thickness ratio of the two layers has to be in a certain range for stable coating, otherwise different types of coating defects would appear. The effects of viscosity, wrapping angle, surface tension, and web tension were studied. It was found that the viscosity ratio of the top layer to the carrier layer is the most critical factor; a large ratio is more helpful in reducing the thickness of the top layer. Increasing the wrapping angle, web tension, and surface tension of the top layer can also decrease the coating thickness of the top layer. The drying load is reduced substantially owing to the significant reduction of the top layer thickness. It was estimated that 50-90% of the energy required for drying could be saved by introducing a carrier layer in this study. POLYM. ENG. SCI., 49:1784-1792, 2009. (C) 2009 Society of Plastics Engineers