Polarizing Filters reduce reflections and glare, they are neutral color and can be used for color or black and white imaging.
As the light coming from the sun is not polarized parts of the light become partially polarized due to the scattering of particles in the atmosphere. This scattering reduces the transparency of the air and creates haze in the distance and the blue in the sky on a sunny day.
Polarization also controls in the reflections of light on the original color of the surface.
The Heliopan Polarizer improves the color of the sky, (in distant pictures, mountain scenes, etc.) it reduces the bluish cast in landscapes and increses the blue color of the sky. The effect is strongest at 90 angle to the sun.
In addition polarizers enhance the color saturation of the scene by suppressing the reflections on the surface, undesired reflections are largely eliminated.
While increasing color saturation with software can also improve the color saturation, this procedure will not replace the need for a poloraizer. For digicams we recommend using a circular polarizer, linear polarizers may result in incorrect exposure or focus under some lighting conditions.