A method and system for designing a photomask. The method provides a single machine methodology for inspecting photomasks having regions that repeat and regions that do not repeat. The method includes generating a chip dataset representing an integrated circuit chip design to be included in a cell region of a photomask, generating a kerf dataset to be included in the cell region, generating a kerf copy dataset, and merging the chip dataset, the kerf dataset and the kerf copy dataset into a photomask dataset representing a pattern of clear and opaque regions of the photomask.