A method for controlling the deposition of vaporized organic material onto a substrate surface, includes providing a heating device to produce vaporized organic material; providing a manifold having at least one aperture through which vaporized organic material passes for deposition onto the substrate surface; providing a controller operating independently of the heating device and effective in a first condition for limiting the passage of vaporized organic material through the aperture, and effective in a second condition for facilitating the passage of vaporized organic material through the aperture; and wherein the heating device, or the controller, or both are contiguous to the manifold.