1. A method of reducing proximity effects in a lithographic process wherein an integrated circuitry pattern is transferred from a mask onto a semiconductor substrate, the method comprising: defining a desired spacing between a main feature which is to reside on the mask and which is to be transferred onto the substrate and an adjacent proximity effects-correcting feature; and after said defining, adjusting the dimensions of the main feature relative to the proximity effects-correcting feature to achieve a desired transferred main feature dimension.