52mm Red #25A (HMC) Multi-Coated Glass Filter for Black & White Film Filter Systems - For Black & White Film This Hoya Red #25A filter is ideal for strong contrast improvement since it absorbs green and blue completely and enhances red. In addition to contrast control, red filters enhance skin tones, tonal corrections and are effective for more dramatic landscapes. Multicoated to minimize reflection at the filter surfaces which reduces flare and ghosting.