The Formatt-Hitech 6.6 x 6.6" 0.6 hard edge neutral density graduated filter helps to specifically darken skies and other bright areas of the image. The filter is densest at the edge and gradually lightens towards the middle, with a clear transition line between the density areas and the clear areas. By having only a portion of neutral density on the filter, you can selectively darken areas of an image whilst allowing the part of the image in the clear section to receive normal exposure. Neutral density filters do not affect image colouration and the 0.6 density provides a 2-stop reduction in light entering the lens. Formatt-Hitech glass filters are manufactured from high-quality Schott Superwite glass for exceptional clarity and maintained light transmission. This filter measures 6.6 x 6.6" / 167.6 x 167.6mm. - 0.6 hard edge ND graduated filter for darkening skies and other bright areas of the image. - Provides a 2-stop light reduction in selected areas. - The hard edge transition is ideal for situations where there is a clear and distinct separation line between bright and dark areas of the image. - Neutral density filters do not affect overall image colouration.