Blue sun reflected from water: optical lessons from observations of nature

Specular reflections of the sun from a wind-rippled water surface combine to form a glitter pattern. These reflections are expected to not alter the perceived color of the sun (or other light source), but when the light is reflected near the Brewster angle, the highly polarized glints can appear blue when observed through a polarizer or polarizing sun glasses. This blue appearance is a result of blue light leakage through a standard film polarizer oriented orthogonal to the plane of polarization of the reflected light. Measurements are shown of crossed-polarizer transmission spectra exhibiting blue and near infrared light leakage for photographic polarizing filters and polarized sunglasses. A variety of photographs are shown to confirm blue light leakage as the source of the blue glint color.