The Hoya 67mm W12 Umber warming color conversion multi-coated glass filter is a precision optical accessory designed for photographers using tungsten-balanced film, such as Cinestill 800T, to correct color temperature shifts. It warms ambient light by 2200 Kelvin, equivalent to a +120 mired shift, imparting a dark amber hue that neutralizes blue casts in daylight or with 5500 K light sources like flashes and studio strobes. This filter is the successor model to the W10, offering a stronger warming effect for more neutral results with standard tungsten films. Constructed from high-quality glass, it features Hoya's Multi-Coat (HMC) technology to minimize reflections, reduce flare and ghosting, and achieve over 97% average light transmission, enhancing compatibility with modern multi-coated lenses. With a diameter of 67 mm, it ensures durability and reliable performance for professional and enthusiast photographers seeking accurate color rendition in various lighting conditions.