In an electronic design automation technique for optical proximity correction, an optimized mask function that has values other than those allowed for a particular mask type, such as 0 and 1 for a chrome-on-glass binary mask, evolves it to a solution restricted to these values or narrow intervals near them. The technique "regularizes" the solution by mixing in a new cost functional that encourages the mask to assume the desired values. The mixing in may be done over one or more steps or even "quasistatically," in which the total cost functional and the mask is brought from pure goodness-of-fit to the printed layout for given conditions to pure manufacturability by keeping the total cost functional minimized step-by-step. A goal of this gradual mixing-in is to do thermodynamically optimal work on the mask function to bring it to manufacturable values.