One inventive aspect relates to a method of lithographic processing of a device). The method may be performed using a lithographic processing system and applying a reticle). Lithographic processing of a device typically is characterized by focus conditions, a set of selectable lithographic processing system parameter values and selectable reticle parameter values. The method of configuring the lithographic processing comprises receiving values for the lithographic processing system parameters and for the reticle parameters. The method further comprises receiving focus conditions for the lithographic processing, the focus conditions allowing separation of image performance effects due to lithographic processing system aberrations and image performance effects due to reticle shadowing effects. The method further comprises determining image performance effects due to lithographic processing system aberrations and the image performance due to reticle shadowing effects. Furthermore, a test kit for performing a method for lithographic processing devices such as a lithographic processing system or a reticle adapted for using the method is described.