1. A method of determining dynamic scan field curvature associated with a photolithographic scanner having a projection lens, the method comprising: exposing an array of focusing fiducials in a reticle of the scanner onto a substrate coated with a suitable recording media; rotating and realigning the substrate; exposing a second array of focusing fiducials through the reticle, offset from the first exposed array of focusing fiducials by a predetermined position to produce a printed array of offset focusing fiducials; and calculating dynamic scan field curvature in accordance with measurements of the focusing fiducials and a dynamic lens field curvature map for the photolithographic scanner.