These were bench tested results which were not noticeable to the naked eye. The following article will hopefully end them. Polarizing Filters Polarizing screens do three things that are useful to a photographer. They darken blue skies, they remove or reduce reflections from non metallic surfaces such as water and glass, and they penetrate haze. To understand how polarizing screens work, you need to know a few things about the nature of light.
Light rays travel in straight lines.
Lights rays also vibrate in all directions perpendicular to their direction of travel. When a light ray hits a nonmetallic surface the vibration in only one direction , or plane, is reflected completely. Depending upon the angle at which you're viewing the light reflected from an object , vibrations in other planes are reduced or eliminated completely. The light from a blue sky is polarized because it is reflected off the nonmetallic particle in the atmosphere. A polarizing screen will pass the vibrations of a light ray in one plane.