A method and apparatus to expose photosensitive printing plates with a predetermined radiation density from the main side (top) and a predetermined radiation density from the back side (bottom). The method comprises executing the main exposure with a time delay after the back exposure. The time delay between back exposure and main exposure is optimized to create smaller stable single dot elements on the photosensitive printing plate after processing and smaller single element dot sizes printed on the print substrate. The plate floor may be adjusted by performing a back-side-only exposure prior to executing the combined back and main exposure with the time delay.