Abstract: A method for controlling the slope of the edge gradient of a layer of vapor deposition material onto a substrate from an evaporation source of vapor deposition material comprising the steps of forming a flux of vapor deposition material having an effective source cross-sectional area and shape from an evaporation source of a vapor deposition material located at a known position, indexing a deposition mask having a plurality of apertures extending therethrough such that the mask is in a spaced relationship from the source defining a source-to-mask distance and positioned in the flux of vapor deposition material to permit the flux of vapor deposition to pass through the apertures, registering a substrate in a spaced relationship from the deposition mask defining a mask-to-substrate distance to permit the flux of the vapor deposition material passing through the apertures in the deposition mask to impinge onto the substrate forming a layer of vapor deposit material thereon, controlling at least one of the effect