Barbieri Polarization Filter Spectro LFP qbBarbieri Polarization Filter Spectro LFP qb Polarization Filter Spectro LFP qb A polarization filter controls light by blocking out all light except that which is traveling perpendicular to the filter's orientation. This allows the filter to reduce glare off of reflective materials that would otherwise be difficult to measure properly. Reduce the Glare Polarization Filter