A method, apparatus, and system for dynamic range estimation of imaged scenes for automatic exposure control. The method includes computing OD density in insertion regions from OD density information corresponding to the placed layout to identify an OD density gradient. Such extended traps can be line traps and can be further expanded to two and three dimensional configurations. The carbon monoxide is generally in parts-per-million quantities and will achieve the desired results in quantities less than 5,000 ppm, preferably less than 2,000 ppm.