Polarizing filters, or polarizing filters for short, are light filters in which the light is polarized and which therefore only allow light waves of a certain oscillation plane to pass. Stray light that oscillates in several planes is filtered out.
By polarizing the light and filtering out stray light, reflections from non-metallic surfaces are reduced, and the contrast and color saturation of the image increase considerably. Since polarizing filters allow all colors to pass through equally and have no effect on colors, they can be used in color photography as well as in black and white photography.
Polarizing filters are used in 3D projection and digital photography. In 3D projection, the polarizing filters are used to separate the two images. A polarizing filter is installed in front of each lens of the two projectors, and the polarization of both polarizing filters is offset by 90 °. The viewer uses polarizing glasses and sees the image of one projector with one eye and the image of the other projector with the second eye.
In digital photography, polarizing filters are screwed in front of the lens and the effect of polarization is changed by rotating the filter until the image is shown on the camera display with optimum contrast and color saturation. Furthermore, polarizing filters are found in polarizing glasses, in magneto-optical memories and in TN technology.