Optomechanical systems and photographic processes impose conditions like mirroring and changes of polarity of images, and limitations due to transfer characteristics of optical systems, quality of photographic materials, etching problems. Conventional optical systems will keep on running for some years and it is worthwhile improving their possibilities by compensating some of their limitations. These corrections can be introduced through a computer program at the level of the control tape of the pattern generator. This paper describes two examples of applications showing how to adapt the data to the process. The first one deals with the optimization of the yield and capacity of the principal mask making machines as a function of the size of circuits, by grouping or on the contrary partitionning the chip on the reticle. The second one describes a method for computation of the polarity, orientation and background of a reticle as a function of the polarity and number of steps of a process.