Separation directives for integrated circuit layout design data are formed based upon one or more printing feasibility analyses performed on the layout design data. At least one printing feasibility analysis is performed on layout design data to identify portions of the design that may not be correctly formed or “printed” during a photolithographic process. The geometric element edges involved in a potential printing defect are then identified as edges to be formed using separate masks. Further, separation directives may be created to specifically designate the identified edges as edges to be formed using separate masks in a photolithographic manufacturing process.