This work employs U-V-visible extinction spectroscopy as anew spectral mapping technique to characterize self-assembled polystyrene microsphere samples produced by convective self-assembly (CSA). This spectroscopic technique was successfully used to analyze the periodic particle arrays produced by the polystyrene template, yielding a detailed characterization of each sample. The CSA-prepared samples proved to be more uniform across a sample as well as more reproducible than previous sample preparation techniques. For the first time, a detailed characterization and quantitative evaluation of the entire sample has been performed by spectroscopic mapping.