A continuous feed coater for coating a length of substrate with vaporized or sprayed material, is disclosed. A specific example is a roll-to-roll coater which includes two lower supply rollers for supporting two webs of uncoated material, and two upper take-up rollers for supporting the webs after they are coated. A central web-support forms a plenum that acts as a deposition chimney or chamber by bringing the two webs into close proximity to each other to form two large walls of the plenum. The ends of the webs are sealed using side dams to form the chimney with a rectangular cross section such that the vapor cannot exit from the edges of the material. The vaporized coating constituents to be deposited on the rolled material are directed into the deposition plenum from a coating material supply source located at the bottom of the plenum, and are exhausted through the top of the plenum. By providing a plenum having two large surface area walls formed of the material to be coated, an extremely efficient coating system is provided. The top of the plenum includes an exhaust system with an orifice plate with a plurality of orifices spaced across the width of the deposition plenum. These orifices restrict gas exhaust to provide the gas and vapor residence time for the materials being used. By further controlling the orifices relative to each other, the differential pressure across the width of the chamber can be controlled to further provide an even coating across the width of the two webs of substrate material. Two different web-handling embodiments are disclosed as is a solid substrate system.