Embodiments are directed to a method and system for determining effective dose of a lithography tool. The method includes performing a series of open frame exposures with the lithography tool on a substrate to produce a set of controlled exposure dose blocks in resist, and then baking and developing the exposed substrate. The method further includes scanning the resultant open frame images with oblique light and capturing the light scattered from the substrate surface. The method further includes creating a haze map from the background signal of the scattered light data, converting the haze map to a graphical image file, and analyzing the graphical image file to determine effective dose of the lithography tool, wherein a brightness of the graphical image file is related to effective dose of the lithography tool.