Air gap variation in an interferometric modulator over a two-dimensional spatial map of the modulator is determined by acquiring a digital photograph of the modulator. Color parameters of individual pixels in the photograph are determined and compared to a model of color parameters as a function of air gap distance. The model and individual pixel color parameters may be plotted on a color space plot for comparison. The determined distances may be plotted over a two-dimensional spatial map of the interferometric modulator to visualize the mirror curvature and air gap variation.