1. A method for controlling a placement of an edge of an image of a reticle pattern formed on a wafer in a lithographic exposure process with an exposure tool having an optical projection system, the method comprising: determining first operational factors based on operation of said exposure tool, first operational factors representing the exposure tool the first operational factors including i) setup parameters of said exposure tool; ii) optical aberrations of an illuminator and a projection lens of the optical projection system, the illuminator and the projection lens being in optical communication through a reticle carrying the reticle pattern; and iii) a signature of the optical system of the exposure tool; optimizing, with a computer device, a merit function to produce a value of change of a setup parameter from the setup parameters, wherein the merit function represents a contribution of a first operational factor, from the first operational factors, to a first measure of a shift in a position of an edge of said image with respect to a target position thereof; and modifying, based on said value of change, the exposure tool by changing at least one of a) one or more of a presence, position, orientation, size and shape of an optical component of the optical projection system; and b) a parameter of scanning synchronization of the exposure tool to form an image with a second measure of said shift, wherein the second measure is reduce in comparison with the first measure.