The Hoya 77mm C2 Blue Cooling Color Correction Multi-Coated Glass Filter offers precise color temperature adjustment for professional photography applications. This round 77mm filter cools ambient light by 200 Kelvin with a -20 Mired shift and adds a blue tone to correct excessive warm lighting conditions. Constructed from high-quality optical glass with multi-coating, it achieves over 97 percent average light transmission with minimal reflection, lens flare, and ghosting. The filter is specifically designed for color correction when using tungsten-balanced film with daylight sources or daylight-balanced film with warm artificial lighting. It effectively neutralizes the orange cast from incandescent bulbs, candlelight, and warm ambient conditions, ensuring accurate color reproduction and enhanced skin tones. The multi-coated surface complements modern multi-coated lenses and maintains image sharpness and contrast across the entire visible spectrum. With its robust glass construction and precise threading, this filter provides reliable performance for photographers who require exact color temperature control in various shooting environments. The cooling effect enhances color saturation and balance while preserving natural tonal relationships in portrait and landscape photography applications.