A technique for determining, without having to perform optical proximity correction, when the result of optical proximity correction will fail to meet the design requirements for printability. A disclosed embodiment has application to a process for producing a photomask for use in the printing of a pattern on a wafer by exposure with optical radiation to optically image the photomask on the wafer. A method is set forth for checking the printability of a target layout proposed for defining the photomask, including the following steps: deriving a system of inequalities that expresses a set of design requirements with respect to the target layout; and checking the printability of the target layout by determining whether the system of inequalities is feasible.