The 4 x 5.65" Ultra Contrast Filter from Tiffen Âhelps to open your shadows by using the ambient light surrounding the image area as well as the light in the actual image itself. It lowers contrast uniformly throughout, with little or no loss of sharpness within the scene, even where there are varying degrees of brightness. Shadow areas will reveal more detail but without any flare or halation from direct light sources or bright reflections. The Ultra Contrast works similar to a Tiffen Low Contrast filter with the difference being that it reduces contrast throughout the entire image whereas a Low Contrast filter will only open the shadows. The #1 Ultra Contrast filter is the first full grade this filter is available in. More of the surrounding light is employed to open your shadows yet you will still not see any highlight flare or halation. Sharpness continues to be consistent. Tiffen's ColorCore glass is produced through a process that entails permanently laminating the filter material in between two pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision aluminum rings.