The effect of transparent and opaque reticle defects is examined with four illumination schemes used to enhance stepper resolution: standard with sigma 0.6, quadrapole, annular, and high coherence, sigma 0.3. It is found that transparent defects have greater printability than opaque defects. This difference in printability is more significant when the defect causes more than a 20% CD loss. In addition, defects centered between geometry defects have greater printability than opaque defects, and quadrapole illumination enhances the printability of defects compared to standard illumination. Process window analysis is used to shot that if both a reticle defect and a reticle CD error occur at the same point, the CD error effects add or subtract depending on their polarity. If +/- 10% CD control is required on 100% of the final gates of a circuit, one can not assign all 10% just to reticle defects. It is necessary to allow greater than +/- 10% variation on the wafer, or to allow less than 10% variation from reticle defects.